diff --git a/index.bs b/index.bs
index b2809384f..1cc5a3a95 100644
--- a/index.bs
+++ b/index.bs
@@ -2804,7 +2804,7 @@ Keys in {{GetClientCapabilitiesResult}} SHOULD be members of {{ClientCapability}
 
 When the value for a given capability is [TRUE], the feature is known to be currently supported by the client.
 When the value for a given capability is [FALSE], the feature is known to be not currently supported by the client.
-When a given capability is `undefined`, the availibility of the client feature is not known.
+When a given capability is `undefined`, the availability of the client feature is not known.
 
 Note: Invoking this method from a [=browsing context=] where the [=Web Authentication API=] is "disabled" according to the [=allowed to use=] algorithm—i.e., by a [=permissions policy=]—will result in the promise being rejected with a {{DOMException}} whose name is "{{NotAllowedError}}". See also [[#sctn-permissions-policy]].