diff --git a/src/emacs/lean-syntax.el b/src/emacs/lean-syntax.el
index b70859b71..2c6681c0b 100644
--- a/src/emacs/lean-syntax.el
+++ b/src/emacs/lean-syntax.el
@@ -107,7 +107,7 @@
            (group (or "inductive" "theorem" "axiom" "lemma" "hypothesis" "definition" "constant"))
            word-end
            (zero-or-more (or whitespace "(" "{" "["))
-           (group (zero-or-more (not (any " \t\n\r")))))
+           (group (zero-or-more (not (any " \t\n\r\.")))))
       (2 'font-lock-function-name-face))
      ("\\(set_option\\)[ \t]*\\([^ \t\n]*\\)" (2 'font-lock-constant-face))
      ;; place holder