diff --git a/doc/api/cluster.md b/doc/api/cluster.md
index d22c46ee383623..ac199c34a3755a 100644
--- a/doc/api/cluster.md
+++ b/doc/api/cluster.md
@@ -761,7 +761,7 @@ The `addressType` is one of:
 * `4` (TCPv4)
 * `6` (TCPv6)
 * `-1` (Unix domain socket)
-* `'udp4'` or `'udp6'` (UDP v4 or v6)
+* `'udp4'` or `'udp6'` (UDPv4 or UDPv6)
 
 ## Event: `'message'`