diff --git a/langfilter/Spans.hs b/langfilter/Spans.hs
index 7d1fbfe..618ed0f 100644
--- a/langfilter/Spans.hs
+++ b/langfilter/Spans.hs
@@ -21,6 +21,7 @@ spans = \case
     | Just txt'         <- enclosed "{"  "}"  txt -> lang txt'
     | Just txt'         <- enclosed "!"  "!"  txt -> pure $ abbr txt'
     | Just txt'         <- enclosed "*"  "*"  txt -> pure $ mark txt'
+    | Just txt'         <- enclosed "@"  "@"  txt -> pure $ dfn txt'
   i -> pure i
 
 ipaA, ipaB, ipaN, abbr, mark :: Text -> Inline
@@ -29,6 +30,7 @@ ipaB = Span (cls ["ipa", "ipa-broad"])  . text'
 ipaN = Span (cls ["ipa", "ipa-narrow"]) . text'
 abbr = Span (cls ["abbr"])              . text' . endash
 mark txt = RawInline "html" $ "<mark>" <> txt <> "</mark>"
+dfn txt = RawInline "html" $ "<dfn>" <> txt <> "</dfn>"
 
 surround :: Text -> Text -> Text
 surround s txt = s <> txt <> s