diff --git a/relationships/definition.json b/relationships/definition.json
index 4bb3015..79577d4 100644
--- a/relationships/definition.json
+++ b/relationships/definition.json
@@ -1004,6 +1004,20 @@
       ],
       "name": "knows"
     },
+    {
+      "description": "Represents the semantic link of describing another object.",
+      "format": [
+        "misp"
+      ],
+      "name": "describes"
+    },
+    {
+      "description": "Represents the semantic link of extending another object.",
+      "format": [
+        "misp"
+      ],
+      "name": "extends"
+    },
     {
       "description": "owns",
       "format": [