diff --git a/src/main/java/ip/syssrc/string/Vocab.java b/src/main/java/ip/syssrc/string/Vocab.java
index fadbdedb..f1e11cc4 100644
--- a/src/main/java/ip/syssrc/string/Vocab.java
+++ b/src/main/java/ip/syssrc/string/Vocab.java
@@ -37,7 +37,7 @@ public static String prefixes(String prefix, String... groups) {
             groups[i] = prefix.concat(groups[i]);
         }
 
-        uni += String.join(":: ", groups);
+        uni += String.join(" :: ", groups);
 
         return new String(uni);
     }