[jaak]

I believe the AS/400 calls it Field Exit. One of the things I used to do for new users was remap Field Exist to Enter in the IBM 5250 emulation software. Then the enter key acted like the user expected (on a real 5250 terminal there is a separate physical Enter key located where the right control key is on modern keyboards).

Explaining Field Exit vs Enter was something most users didn't get. However, they did understand Enter as like a submit button (like on web pages) and were fine selecting fields with the mouse.

[ASalazarMX]

It's been many years, but wasn't that a key that allowed you to change input fields, just like TAB does it with web pages? IIRC that key was managed purely client-side.