diff --git a/spec/index.html b/spec/index.html
index 98f90d7..05e2fbe 100644
--- a/spec/index.html
+++ b/spec/index.html
@@ -539,7 +539,7 @@ <h2>RDF Graphs</h2>
 
   <p>An <dfn>RDF graph</dfn> is a set of <a>RDF triples</a>.</p>
 
-  <p>An RDF triple is said to be <dfn data-lt="asserted|asserted triple">asserted</dfn> in an RDF graph if it is an element of the RDF graph.</p>
+  <p>An RDF triple is said to be <dfn id="dfn-asserted-triple" data-lt="asserted|asserted triple">asserted</dfn> in an RDF graph if it is an element of the RDF graph.</p>
 
   <section id="section-triples">
     <h3>Triples</h3>