diff --git a/pkgs/applications/misc/wordnet/default.nix b/pkgs/applications/misc/wordnet/default.nix
index f1bc06d395c7..b93295850bcd 100644
--- a/pkgs/applications/misc/wordnet/default.nix
+++ b/pkgs/applications/misc/wordnet/default.nix
@@ -1,7 +1,7 @@
 {stdenv, fetchurl, tcl, tk, xlibsWrapper, makeWrapper}:
 
-let version = "3.0"; in
-stdenv.mkDerivation {
+stdenv.mkDerivation rec {
+  version = "3.0";
   name = "wordnet-${version}";
   src = fetchurl {
     url = "http://wordnetcode.princeton.edu/${version}/WordNet-${version}.tar.bz2";