diff --git a/src/structs.h b/src/structs.h
index 97eae57..abfe6cd 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1221,6 +1221,15 @@
 };
 typedef struct dictitem_S dictitem_T;
 
+/* A dictitem with a 16 character key (plus NUL). */
+struct dictitem16_S
+{
+    typval_T	di_tv;		/* type and value of the variable */
+    char_u	di_flags;	/* flags (only used for variable) */
+    char_u	di_key[17];	/* key */
+};
+typedef struct dictitem16_S dictitem16_T;
+
 #define DI_FLAGS_RO	1  /* "di_flags" value: read-only variable */
 #define DI_FLAGS_RO_SBX 2  /* "di_flags" value: read-only in the sandbox */
 #define DI_FLAGS_FIX	4  /* "di_flags" value: fixed: no :unlet or remove() */