diff --git a/lexicons/my/spoor/content/title.json b/lexicons/my/spoor/content/defs.json
similarity index 78%
rename from lexicons/my/spoor/content/title.json
rename to lexicons/my/spoor/content/defs.json
index 3368a47..f13f8fd 100644
--- a/lexicons/my/spoor/content/title.json
+++ b/lexicons/my/spoor/content/defs.json
@@ -1,15 +1,17 @@
 {
   "lexicon": 1,
-  "id": "my.spoor.content.title",
+  "id": "my.spoor.content.defs",
   "defs": {
-    "main": {
+    "title": {
       "type": "object",
       "properties": {
         "translationType": { 
           "type": "string",
           "format": "nsid",
           "knownValues": [
-            "#titleHomophonic", "#titleNative", "#titleTranslation"
+            "my.spoor.content.defs#titleHomophonic",
+            "my.spoor.content.defs#titleNative",
+            "my.spoor.content.defs#titleTranslation"
           ]
         },
         "lang": {
diff --git a/lexicons/my/spoor/content/external.json b/lexicons/my/spoor/content/external.json
index fc6f470..fd272af 100644
--- a/lexicons/my/spoor/content/external.json
+++ b/lexicons/my/spoor/content/external.json
@@ -14,7 +14,7 @@
             "minLength": 1,
             "items": {
               "type": "ref",
-              "ref": "my.spoor.content.title"
+              "ref": "my.spoor.content.defs#title"
             }
           },
           "source": {
diff --git a/lexicons/my/spoor/content/media.json b/lexicons/my/spoor/content/media.json
index e8897c2..ec383d1 100644
--- a/lexicons/my/spoor/content/media.json
+++ b/lexicons/my/spoor/content/media.json
@@ -14,7 +14,7 @@
             "minLength": 1,
             "items": {
               "type": "ref",
-              "ref": "my.spoor.content.title"
+              "ref": "my.spoor.content.defs#title"
             }
           },
           "durationData": {
diff --git a/lexicons/my/spoor/log/activity.json b/lexicons/my/spoor/log/activity.json
index adb3a1e..f3035fb 100644
--- a/lexicons/my/spoor/log/activity.json
+++ b/lexicons/my/spoor/log/activity.json
@@ -15,7 +15,7 @@
           "progress": {
             "type": "union",
             "refs": [
-              "#progressIndex"
+              "my.spoor.log.activity#indexProgress"
             ]
           },
           "performedAt": {
@@ -31,13 +31,9 @@
         }
       }
     },
-    "progressIndex": {
-      "type": "object",
-      "description": "The index of the content consumed. Content must be indexable",
-      "required": [ "index" ],
-      "properties": {
-        "index": { "type": "integer" }
-      }
+    "indexProgress": {
+      "type": "integer",
+      "description": "The index of the content consumed. Content must be indexable"
     }
   }
 }