diff --git a/index.bs b/index.bs
index 295c0973..123cb2da 100644
--- a/index.bs
+++ b/index.bs
@@ -142,8 +142,8 @@ The terms {{ReadableStream}} and {{WritableStream}} are defined in
 
 # Protocol concepts # {#protocol-concepts}
 
-A <dfn>WebTransport session</dfn> is a session of WebTransport over HTTP/3.
-There may be multiple [=WebTransport session=]s on one [=connection=], when pooling is enabled.
+A <dfn for="protocol">WebTransport session</dfn> is a session of WebTransport over HTTP/3.
+There may be multiple [=WebTransport sessions=] on one [=connection=], when pooling is enabled.
 
 [=WebTransport session=] has the following capabilities defined in [[!WEB-TRANSPORT-HTTP3]].