diff --git a/docs/source/resources/define-metadata.rst b/docs/source/resources/define-metadata.rst
index 1853b89ba1..4ba1cd9357 100644
--- a/docs/source/resources/define-metadata.rst
+++ b/docs/source/resources/define-metadata.rst
@@ -1730,6 +1730,9 @@ variables are booleans.
        is ppc64le.
    * - osx
      - True if the platform is macOS.
+   * - arm64
+     - True if the platform is macOS and the Python architecture
+       is arm64.
    * - unix
      - True if the platform is either macOS or Linux.
    * - win
@@ -1758,6 +1761,8 @@ variables are booleans.
    * - np
      - The NumPy version as an integer such as ``111``. See the
        CONDA_NPY :ref:`environment variable <build-envs>`.
+   * - build_platform
+     - The native subdir of the conda executable
 
 The use of the Python version selectors, `py27`, `py34`, etc. is discouraged in
 favor of the more general comparison operators.  Additional selectors in this
diff --git a/docs/source/user-guide/environment-variables.rst b/docs/source/user-guide/environment-variables.rst
index 2f4ad241c9..58ecce2a1c 100644
--- a/docs/source/user-guide/environment-variables.rst
+++ b/docs/source/user-guide/environment-variables.rst
@@ -127,6 +127,8 @@ inherited from the shell environment in which you invoke
        source file.
    * - STDLIB_DIR
      - Python standard library location.
+   * - build_platform
+     - The native subdir of the conda executable
 
 Unix-style packages on Windows, which are usually statically
 linked to executables, are built in a special ``Library``