add api notable terminology

docs/docs/api/terminology.md

@@ -0,0 +1,12 @@
+# Notable Terminology
+
+Similar to the userland terminology document - Tachi has some internal terminology that you should
+be familiar with.
+
+## GPT
+
+Refers to "Game + Playtype" - a combination of a game and its playtype.
+
+## UGPT
+
+Refers to "User on Game + Playtype" - A user's "something" on a game and that playtype.

docs/mkdocs.yml

@@ -43,6 +43,7 @@ nav:
   - API Reference:
     - "api/overview.md"
     - "api/auth.md"
+    - "api/terminology.md"
 
     - Endpoints:
       - "api/routes/example.md"