diff --git a/css/css-animations/display-interpolation.html b/css/css-animations/display-interpolation.html
index 4c3f8f8d217d621..fb2503ac8a41556 100644
--- a/css/css-animations/display-interpolation.html
+++ b/css/css-animations/display-interpolation.html
@@ -26,7 +26,7 @@
 
 test_interpolation({
   property: 'display',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'block',
   to: 'none',
 }, [
@@ -43,7 +43,7 @@
 // can be worked around by using @initial.
 test_interpolation({
   property: 'display',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'none',
   to: 'block',
   'CSS Transitions with transition: all': alwaysBlock,
@@ -65,14 +65,14 @@
 
 test_interpolation({
   property: 'display',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'block',
   to: 'block'
 }, alwaysBlock);
 
 test_interpolation({
   property: 'display',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'none',
   to: 'none'
 }, alwaysNone);
diff --git a/css/css-contain/content-visibility/content-visibility-interpolation.html b/css/css-contain/content-visibility/content-visibility-interpolation.html
index 4b3cf856494e3ea..55f8c7e5af8e6e9 100644
--- a/css/css-contain/content-visibility/content-visibility-interpolation.html
+++ b/css/css-contain/content-visibility/content-visibility-interpolation.html
@@ -26,7 +26,7 @@
 
 test_interpolation({
   property: 'content-visibility',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'visible',
   to: 'hidden',
 }, [
@@ -40,7 +40,7 @@
 
 test_interpolation({
   property: 'content-visibility',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
   from: 'hidden',
   to: 'visible',
 }, [
diff --git a/css/css-position/overlay/overlay-transition-backdrop-entry.html b/css/css-position/overlay/overlay-transition-backdrop-entry.html
index 7db33eb85dea74e..8737dc58f92ae01 100644
--- a/css/css-position/overlay/overlay-transition-backdrop-entry.html
+++ b/css/css-position/overlay/overlay-transition-backdrop-entry.html
@@ -13,7 +13,7 @@
     transition-delay: 2s;
     transition-property: overlay;
     transition-duration: 2s;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
   }
   [popover]::backdrop {
     background-color: blue;
diff --git a/css/css-position/overlay/overlay-transition-backdrop.html b/css/css-position/overlay/overlay-transition-backdrop.html
index fde933da5dbbbdb..30d40e111f9b676 100644
--- a/css/css-position/overlay/overlay-transition-backdrop.html
+++ b/css/css-position/overlay/overlay-transition-backdrop.html
@@ -8,7 +8,7 @@
     display: block;
     visibility: hidden;
     transition: overlay 60s step-end;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
   }
   [popover]::backdrop {
     background-color: green;
diff --git a/css/css-position/overlay/overlay-transition-finished.html b/css/css-position/overlay/overlay-transition-finished.html
index b2322389d06f102..7e22cb3cf64b9f4 100644
--- a/css/css-position/overlay/overlay-transition-finished.html
+++ b/css/css-position/overlay/overlay-transition-finished.html
@@ -20,7 +20,7 @@
   }
   #transition-in {
     transition: overlay 0.1s step-end;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
     background-color: green;
   }
 </style>
diff --git a/css/css-position/overlay/overlay-transition-in-rendering.html b/css/css-position/overlay/overlay-transition-in-rendering.html
index dc1b9ffe20caaa6..0ada33c33cec13f 100644
--- a/css/css-position/overlay/overlay-transition-in-rendering.html
+++ b/css/css-position/overlay/overlay-transition-in-rendering.html
@@ -17,7 +17,7 @@
   }
   #transition-in {
     transition: overlay 60s step-end;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
     background-color: red;
   }
 </style>
diff --git a/css/css-position/overlay/overlay-transition-out-rendering.html b/css/css-position/overlay/overlay-transition-out-rendering.html
index fea03951c5e9ae7..abb01faef7ea994 100644
--- a/css/css-position/overlay/overlay-transition-out-rendering.html
+++ b/css/css-position/overlay/overlay-transition-out-rendering.html
@@ -20,7 +20,7 @@
   }
   #green.transition-enabled {
     transition: overlay 60s step-end;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
   }
 </style>
 <div id="red" popover="manual"></div>
diff --git a/css/css-position/overlay/overlay-transition.html b/css/css-position/overlay/overlay-transition.html
index 9eae2115ff07a6f..efe402373fffc3d 100644
--- a/css/css-position/overlay/overlay-transition.html
+++ b/css/css-position/overlay/overlay-transition.html
@@ -12,7 +12,7 @@
   }
   .enable-transitions :is(#transition-in, #transition-out) {
     transition: overlay 60s step-end;
-    transition-animation-type: discrete;
+    transition-behavior: allow-discrete;
   }
 </style>
 <div id="container">
diff --git a/css/css-properties-values-api/animation/custom-property-transition-custom-ident.html b/css/css-properties-values-api/animation/custom-property-transition-custom-ident.html
index 2f5b55459d5b80c..b7ca1ec785e847c 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-custom-ident.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-custom-ident.html
@@ -11,7 +11,7 @@
   from: "from",
   to: "to",
   expected: "to",
-  animationType: "discrete",
+  behavior: "allow-discrete",
 }, 'A custom property of type <custom-ident> can yield a discrete CSS Transition');
 
 </script>
diff --git a/css/css-properties-values-api/animation/custom-property-transition-image.html b/css/css-properties-values-api/animation/custom-property-transition-image.html
index 8498615a936f6d2..4fd3fe649b0ac55 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-image.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-image.html
@@ -11,7 +11,7 @@
   from: 'url("https://example.com/from")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <image> can yield a CSS Transition');
 
 </script>
diff --git a/css/css-properties-values-api/animation/custom-property-transition-mismatched-list.html b/css/css-properties-values-api/animation/custom-property-transition-mismatched-list.html
index 3007f2aa87dbeab..b7d964b92cb5c7c 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-mismatched-list.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-mismatched-list.html
@@ -11,7 +11,7 @@
   from: '100deg, 200deg',
   to: '300deg',
   expected: '300deg',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <angle># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -19,7 +19,7 @@
   from: '100deg 200deg',
   to: '300deg',
   expected: '300deg',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <angle>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -27,7 +27,7 @@
   from: 'rgb(100, 100, 100), rgb(150, 150, 150)',
   to: 'rgb(200, 200, 200)',
   expected: 'rgb(200, 200, 200)',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <color># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -35,7 +35,7 @@
   from: 'rgb(100, 100, 100) rgb(150, 150, 150)',
   to: 'rgb(200, 200, 200)',
   expected: 'rgb(200, 200, 200)',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <color>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -43,7 +43,7 @@
   from: 'foo, bar',
   to: 'baz',
   expected: 'baz',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <custom-ident># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -51,7 +51,7 @@
   from: 'foo bar',
   to: 'baz',
   expected: 'baz',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <custom-ident>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -59,7 +59,7 @@
   from: 'url("https://example.com/foo"), url("https://example.com/bar")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <image># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -67,7 +67,7 @@
   from: 'url("https://example.com/foo") url("https://example.com/bar")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <image>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -75,7 +75,7 @@
   from: '100, 200',
   to: '300',
   expected: '300',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <integer># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -83,7 +83,7 @@
   from: '100 200',
   to: '300',
   expected: '300',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <integer>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -91,7 +91,7 @@
   from: '100px, 200px',
   to: '300%',
   expected: '300%',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <length-percentage># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -99,7 +99,7 @@
   from: '100px 200px',
   to: '300%',
   expected: '300%',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <length-percentage>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -107,7 +107,7 @@
   from: '100px, 200px',
   to: '300px',
   expected: '300px',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <length># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -115,7 +115,7 @@
   from: '100px 200px',
   to: '300px',
   expected: '300px',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <length>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -123,7 +123,7 @@
   from: '100, 200',
   to: '300',
   expected: '300',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <number># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -131,7 +131,7 @@
   from: '100 200',
   to: '300',
   expected: '300',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <number>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -139,7 +139,7 @@
   from: '100%, 200%',
   to: '300%',
   expected: '300%',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <percentage># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -147,7 +147,7 @@
   from: '100% 200%',
   to: '300%',
   expected: '300%',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <percentage>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -155,7 +155,7 @@
   from: '100dppx, 200dppx',
   to: '300dppx',
   expected: '300dppx',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <resolution># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -163,7 +163,7 @@
   from: '100dppx 200dppx',
   to: '300dppx',
   expected: '300dppx',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <resolution>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -171,7 +171,7 @@
   from: '100s, 200s',
   to: '300s',
   expected: '300s',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <time># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -179,7 +179,7 @@
   from: '100s 200s',
   to: '300s',
   expected: '300s',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <time>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -187,7 +187,7 @@
   from: 'url("https://example.com/foo"), url("https://example.com/bar")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <url># yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 transition_test({
@@ -195,7 +195,7 @@
   from: 'url("https://example.com/foo") url("https://example.com/bar")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <url>+ yields a discrete CSS Transition if the lists do not contain the same number of values');
 
 </script>
diff --git a/css/css-properties-values-api/animation/custom-property-transition-transform-function.html b/css/css-properties-values-api/animation/custom-property-transition-transform-function.html
index 385c222cd0e8a4f..17ad1067a4dcfcf 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-transform-function.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-transform-function.html
@@ -11,7 +11,7 @@
   from: "translateX(100px)",
   to: "translateX(200px)",
   expected: "translateX(150px)",
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <transform-function> can yield a CSS Transition');
 
 </script>
diff --git a/css/css-properties-values-api/animation/custom-property-transition-transform-list.html b/css/css-properties-values-api/animation/custom-property-transition-transform-list.html
index 1e5cef194d09a6a..c9d3cb94d143d2f 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-transform-list.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-transform-list.html
@@ -11,7 +11,7 @@
   from: "translateX(100px) scale(2)",
   to: "translateX(200px) scale(4)",
   expected: "translateX(150px) scale(3)",
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <transform-list> can yield a CSS Transition');
 
 </script>
diff --git a/css/css-properties-values-api/animation/custom-property-transition-url.html b/css/css-properties-values-api/animation/custom-property-transition-url.html
index 600e7ddb1db75dc..c5d438e54936027 100644
--- a/css/css-properties-values-api/animation/custom-property-transition-url.html
+++ b/css/css-properties-values-api/animation/custom-property-transition-url.html
@@ -11,7 +11,7 @@
   from: 'url("https://example.com/from")',
   to: 'url("https://example.com/to")',
   expected: 'url("https://example.com/to")',
-  animationType: 'discrete',
+  behavior: 'allow-discrete',
 }, 'A custom property of type <url> can yield a discrete CSS Transition');
 
 </script>
diff --git a/css/css-properties-values-api/resources/utils.js b/css/css-properties-values-api/resources/utils.js
index be51111fd37357e..fc3a5993cf56655 100644
--- a/css/css-properties-values-api/resources/utils.js
+++ b/css/css-properties-values-api/resources/utils.js
@@ -204,8 +204,8 @@ function transition_test(options, description) {
     });
 
     target.style.transition = `${options.transitionProperty} 1s -500ms linear`;
-    if (options.animationType) {
-      target.style.transitionAnimationType = options.animationType;
+    if (options.behavior) {
+      target.style.transitionBehavior = options.behavior;
     }
     target.style.setProperty(customProperty, options.to);
 
diff --git a/css/css-transitions/all-with-discrete.tentative.html b/css/css-transitions/all-with-discrete.tentative.html
index 8e428e0f8ce5dc9..c8734f28029e704 100644
--- a/css/css-transitions/all-with-discrete.tentative.html
+++ b/css/css-transitions/all-with-discrete.tentative.html
@@ -13,7 +13,7 @@
   width: 100px;
   height: 100px;
   transition: all 1s;
-  transition-animation-type: discrete;
+  transition-behavior: allow-discrete;
 }
 #target.animated {
   float: right;
@@ -30,5 +30,5 @@
   target.classList.add('animated');
   await waitForAnimationFrames(1);
   assert_true(transitionstartFired);
-}, 'transition:all with transition-animation-type:discrete should animate discrete properties.');
+}, 'transition:all with transition-behavior:allow-discrete should animate discrete properties.');
 </script>
diff --git a/css/css-transitions/parsing/transition-behavior.html b/css/css-transitions/parsing/transition-behavior.html
index a8fcc6bb09c3e05..08ad3a6adf4da0c 100644
--- a/css/css-transitions/parsing/transition-behavior.html
+++ b/css/css-transitions/parsing/transition-behavior.html
@@ -7,51 +7,51 @@
 <script src="/css/support/computed-testcommon.js"></script>
 <div id="target"></div>
 <script>
-test_valid_value('transition-animation-type', 'normal');
-test_computed_value('transition-animation-type', 'normal');
+test_valid_value('transition-behavior', 'normal');
+test_computed_value('transition-behavior', 'normal');
 
-test_valid_value('transition-animation-type', 'discrete');
-test_computed_value('transition-animation-type', 'discrete');
+test_valid_value('transition-behavior', 'allow-discrete');
+test_computed_value('transition-behavior', 'allow-discrete');
 
-test_valid_value('transition', 'discrete display', 'display 0s ease 0s discrete');
-test_computed_value('transition', 'discrete display', 'display 0s ease 0s discrete');
+test_valid_value('transition', 'allow-discrete display', 'display 0s ease 0s allow-discrete');
+test_computed_value('transition', 'allow-discrete display', 'display 0s ease 0s allow-discrete');
 
-test_valid_value('transition', 'discrete display 3s', 'display 3s ease 0s discrete');
-test_computed_value('transition', 'discrete display 3s', 'display 3s ease 0s discrete');
+test_valid_value('transition', 'allow-discrete display 3s', 'display 3s ease 0s allow-discrete');
+test_computed_value('transition', 'allow-discrete display 3s', 'display 3s ease 0s allow-discrete');
 
-test_valid_value('transition', 'discrete display 3s 1s', 'display 3s ease 1s discrete');
-test_computed_value('transition', 'discrete display 3s 1s', 'display 3s ease 1s discrete');
+test_valid_value('transition', 'allow-discrete display 3s 1s', 'display 3s ease 1s allow-discrete');
+test_computed_value('transition', 'allow-discrete display 3s 1s', 'display 3s ease 1s allow-discrete');
 
-test_valid_value('transition', 'discrete display 3s ease-in-out', 'display 3s ease-in-out 0s discrete');
-test_computed_value('transition', 'discrete display 3s ease-in-out', 'display 3s ease-in-out 0s discrete');
+test_valid_value('transition', 'allow-discrete display 3s ease-in-out', 'display 3s ease-in-out 0s allow-discrete');
+test_computed_value('transition', 'allow-discrete display 3s ease-in-out', 'display 3s ease-in-out 0s allow-discrete');
 
-test_valid_value('transition', 'discrete display 3s ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
-test_computed_value('transition', 'discrete display 3s ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
+test_valid_value('transition', 'allow-discrete display 3s ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_computed_value('transition', 'allow-discrete display 3s ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
 
 test_invalid_value('transition', 'asdf display');
 test_invalid_value('transition', 'display asdf');
 
 // Putting "discrete" anywhere in the shorthand should still work
-test_valid_value('transition', 'display discrete 3s ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
-test_valid_value('transition', 'display 3s discrete ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
-test_valid_value('transition', 'display 3s ease-in-out discrete 1s', 'display 3s ease-in-out 1s discrete');
-test_valid_value('transition', 'display 3s ease-in-out 1s discrete', 'display 3s ease-in-out 1s discrete');
-test_computed_value('transition', 'display discrete 3s ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
-test_computed_value('transition', 'display 3s discrete ease-in-out 1s', 'display 3s ease-in-out 1s discrete');
-test_computed_value('transition', 'display 3s ease-in-out discrete 1s', 'display 3s ease-in-out 1s discrete');
-test_computed_value('transition', 'display 3s ease-in-out 1s discrete', 'display 3s ease-in-out 1s discrete');
+test_valid_value('transition', 'display allow-discrete 3s ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_valid_value('transition', 'display 3s allow-discrete ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_valid_value('transition', 'display 3s ease-in-out allow-discrete 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_valid_value('transition', 'display 3s ease-in-out 1s allow-discrete', 'display 3s ease-in-out 1s allow-discrete');
+test_computed_value('transition', 'display allow-discrete 3s ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_computed_value('transition', 'display 3s allow-discrete ease-in-out 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_computed_value('transition', 'display 3s ease-in-out allow-discrete 1s', 'display 3s ease-in-out 1s allow-discrete');
+test_computed_value('transition', 'display 3s ease-in-out 1s allow-discrete', 'display 3s ease-in-out 1s allow-discrete');
 
 // Serialization with multiple shorthands, including different order
 test_valid_value('transition',
-  'discrete display, normal opacity, color',
-  'display 0s ease 0s discrete, opacity 0s ease 0s, color 0s ease 0s');
+  'allow-discrete display, normal opacity, color',
+  'display 0s ease 0s allow-discrete, opacity 0s ease 0s, color 0s ease 0s');
 test_computed_value('transition',
-  'discrete display, normal opacity, color',
-  'display 0s ease 0s discrete, opacity 0s ease 0s, color 0s ease 0s');
+  'allow-discrete display, normal opacity, color',
+  'display 0s ease 0s allow-discrete, opacity 0s ease 0s, color 0s ease 0s');
 test_valid_value('transition',
-  'normal opacity, color, discrete display',
-  'opacity 0s ease 0s, color 0s ease 0s, display 0s ease 0s discrete');
+  'normal opacity, color, allow-discrete display',
+  'opacity 0s ease 0s, color 0s ease 0s, display 0s ease 0s allow-discrete');
 test_computed_value('transition',
-  'normal opacity, color, discrete display',
-  'opacity 0s ease 0s, color 0s ease 0s, display 0s ease 0s discrete');
+  'normal opacity, color, allow-discrete display',
+  'opacity 0s ease 0s, color 0s ease 0s, display 0s ease 0s allow-discrete');
 </script>
diff --git a/css/css-transitions/parsing/transition-shorthand.html b/css/css-transitions/parsing/transition-shorthand.html
index 6e7406fd0b9bdbf..fcd14d2a1415ae6 100644
--- a/css/css-transitions/parsing/transition-shorthand.html
+++ b/css/css-transitions/parsing/transition-shorthand.html
@@ -16,7 +16,7 @@
   'transition-duration': '1s',
   'transition-timing-function': 'cubic-bezier(0, -2, 1, 3)',
   'transition-delay': '-3s',
-  'transition-animation-type': 'normal'
+  'transition-behavior': 'normal'
 });
 
 test_shorthand_value('transition', '1s -3s, cubic-bezier(0, -2, 1, 3) top', {
@@ -24,7 +24,7 @@
   'transition-duration': '1s, 0s',
   'transition-timing-function': 'ease, cubic-bezier(0, -2, 1, 3)',
   'transition-delay': '-3s, 0s',
-  'transition-animation-type': 'normal, normal'
+  'transition-behavior': 'normal, normal'
 });
 
 test_shorthand_value('transition', 'cubic-bezier(0, -2, 1, 3) top, 1s -3s', {
@@ -32,7 +32,7 @@
   'transition-duration': '0s, 1s',
   'transition-timing-function': 'cubic-bezier(0, -2, 1, 3), ease',
   'transition-delay': '0s, -3s',
-  'transition-animation-type': 'normal, normal'
+  'transition-behavior': 'normal, normal'
 });
 </script>
 </body>
diff --git a/css/support/interpolation-testcommon.js b/css/support/interpolation-testcommon.js
index 7934127937674e3..115067465feed31 100644
--- a/css/support/interpolation-testcommon.js
+++ b/css/support/interpolation-testcommon.js
@@ -61,15 +61,15 @@
     notAnimatableExpectations: function(from, to, underlying) {
       return expectFlip(from, to, -Infinity);
     },
-    interpolate: function(property, from, to, at, target, animationType) {
+    interpolate: function(property, from, to, at, target, behavior) {
       // Force a style recalc on target to set the 'from' value.
       getComputedStyle(target).getPropertyValue(property);
       target.style.transitionDuration = '100s';
       target.style.transitionDelay = '-50s';
       target.style.transitionTimingFunction = createEasing(at);
       target.style.transitionProperty = property;
-      if (animationType) {
-        target.style.transitionAnimationType = animationType;
+      if (behavior) {
+        target.style.transitionBehavior = behavior;
       }
       target.style.setProperty(property, isNeutralKeyframe(to) ? '' : to);
     },
@@ -90,15 +90,15 @@
     notAnimatableExpectations: function(from, to, underlying) {
       return expectFlip(from, to, -Infinity);
     },
-    interpolate: function(property, from, to, at, target, animationType) {
+    interpolate: function(property, from, to, at, target, behavior) {
       // Force a style recalc on target to set the 'from' value.
       getComputedStyle(target).getPropertyValue(property);
       target.style.transitionDuration = '100s';
       target.style.transitionDelay = '-50s';
       target.style.transitionTimingFunction = createEasing(at);
       target.style.transitionProperty = 'all';
-      if (animationType) {
-        target.style.transitionAnimationType = animationType;
+      if (behavior) {
+        target.style.transitionBehavior = behavior;
       }
       target.style.setProperty(property, isNeutralKeyframe(to) ? '' : to);
     },
@@ -262,7 +262,7 @@
     var from = interpolationTest.options.from;
     var to = interpolationTest.options.to;
     var comparisonFunction = interpolationTest.options.comparisonFunction;
-    var animationType = interpolationTest.options.animationType;
+    var behavior = interpolationTest.options.behavior;
 
     if ((interpolationTest.options.method && interpolationTest.options.method != interpolationMethod.name)
       || !interpolationMethod.supportsProperty(property)
@@ -308,7 +308,7 @@
       }
       interpolationMethod.setup(property, from, target);
       target.interpolate = function() {
-        interpolationMethod.interpolate(property, from, to, expectation.at, target, animationType);
+        interpolationMethod.interpolate(property, from, to, expectation.at, target, behavior);
       };
       target.measure = function() {
         for (var [expectedProp, expectedStr] of Object.entries(expectedProperties)) {