diff --git a/elixir/data.py b/elixir/data.py
index 4dc354f..1f94b57 100755
--- a/elixir/data.py
+++ b/elixir/data.py
@@ -201,6 +201,12 @@ class DB:
             # Map serial number to filename
         self.vers = BsdDB(dir + '/versions.db', ro, PathList, shared=shared)
         self.defs = BsdDB(dir + '/definitions.db', ro, DefList, shared=shared)
+        self.defs_cache = {}
+        NOOP = lambda x: x
+        self.defs_cache['C'] = BsdDB(dir + '/definitions-cache-C.db', ro, NOOP, shared=shared)
+        self.defs_cache['K'] = BsdDB(dir + '/definitions-cache-K.db', ro, NOOP, shared=shared)
+        self.defs_cache['D'] = BsdDB(dir + '/definitions-cache-D.db', ro, NOOP, shared=shared)
+        self.defs_cache['M'] = BsdDB(dir + '/definitions-cache-M.db', ro, NOOP, shared=shared)
         self.refs = BsdDB(dir + '/references.db', ro, RefList, shared=shared)
         self.docs = BsdDB(dir + '/doccomments.db', ro, RefList, shared=shared)
         self.dtscomp = dtscomp
@@ -216,6 +222,10 @@ class DB:
         self.file.close()
         self.vers.close()
         self.defs.close()
+        self.defs_cache['C'].close()
+        self.defs_cache['K'].close()
+        self.defs_cache['D'].close()
+        self.defs_cache['M'].close()
         self.refs.close()
         self.docs.close()
         if self.dtscomp:
diff --git a/elixir/query.py b/elixir/query.py
index ff14d4b..f4e9845 100755
--- a/elixir/query.py
+++ b/elixir/query.py
@@ -188,9 +188,7 @@ class Query:
                 for tok in tokens:
                     even = not even
                     tok2 = prefix + tok
-                    if (even and self.db.defs.exists(tok2) and
-                        (lib.compatibleFamily(self.db.defs.get(tok2).get_families(), family) or
-                        lib.compatibleMacro(self.db.defs.get(tok2).get_macros(), family))):
+                    if even and self.db.defs_cache[family].exists(tok2):
                         tok = b'\033[31m' + tok2 + b'\033[0m'
                     else:
                         tok = lib.unescape(tok)
diff --git a/update.py b/update.py
index 79cb4dc..9d84ff3 100755
--- a/update.py
+++ b/update.py
@@ -189,6 +189,15 @@ class UpdateVersions(Thread):
         db.vers.put(tag, obj, sync=True)
 
 
+def generate_defs_caches():
+    for key in db.defs.get_keys():
+        value = db.defs.get(key)
+        for family in ['C', 'K', 'D', 'M']:
+            if (lib.compatibleFamily(value.get_families(), family) or
+                        lib.compatibleMacro(value.get_macros(), family)):
+                db.defs_cache[family].put(key, b'')
+
+
 class UpdateDefs(Thread):
     def __init__(self, start, inc):
         Thread.__init__(self, name="UpdateDefsElixir")
@@ -256,6 +265,8 @@ class UpdateDefs(Thread):
                         print(f"def {type} {ident} in #{idx} @ {line}")
                     db.defs.put(ident, obj)
 
+        generate_defs_caches()
+
 
 class UpdateRefs(Thread):
     def __init__(self, start, inc):
@@ -586,6 +597,9 @@ project = lib.currentProject()
 print(project + ' - found ' + str(num_tags) + ' new tags')
 
 if not num_tags:
+    # Backward-compatibility: generate defs caches if they are empty.
+    if db.defs_cache['C'].db.stat()['nkeys'] == 0:
+        generate_defs_caches()
     exit(0)
 
 threads_list.append(UpdateIds(tag_buf))