Terminal
Everything between the runtime and a real tty: what the session can do, who owns it while the application runs, and how bytes become input events.
An adapter is anything that can deliver bytes and accept bytes - a Node process, a test harness, an ssh session, a browser canvas. Components never talk to one; they state a role and the theme and the writer resolve it against what the adapter reported.
This is a terminal adapter. A resource adapter, in Documents, is an unrelated thing that happens to share the word.