diff --git a/src/schema/vocab.rnc b/src/schema/vocab.rnc
index 4363ff166786194ea722ff6ab5ad78f19492773a..a696ceb8871f31e39b2abc340baccacc915c3d07 100644
--- a/src/schema/vocab.rnc
+++ b/src/schema/vocab.rnc
@@ -63,6 +63,9 @@ skos.match =
  & element skos:related {
     rdfResource
  }*
+ & element skos:closeMatch {
+    rdfResource
+ }*
 
 skos.altLabel = element skos:altLabel {
    attribute xml:lang { xsd:language }?,