Coronal Mass Ejection?BBCCME ?

This is part of the difficulty; as with VT (Video Tape) if the suffix is a well-known, but unrelated, abbreviation (even if it's obviously not that from the context) it could be confusing.
I'm still leaning towards BBCTTY because (like BBCSDL) the common use of the abbreviation is the very thing we want it to mean!

And the objection that TTY might imply a 'dumb' terminal can be countered by the popular Windows terminal program PuTTY which supports exactly the VT-100/ANSI emulation that the BBC BASIC Console Mode editions expect. Indeed I routinely use PuTTY as the terminal for use with the Raspberry Pi Pico console version of BBC BASIC.