Salute!
Some good points, Vess.
I should hasten to add that your final statement is only accurate for non-FBW aircraft. I also heartily endorse your first statement:
The meaning of "trim" has branched out (as meanings tend to do)
This is especially true for any plane that has an elevator on the horizontal stab, whether fixed or trimmable (as many cargo designs exhibit).
The planes with only moving stabs and no "elevators" still result in a stable pitch/ AoA by moving that stab. But I don't know of any commercial airliners with such a configuration. And the planes with the all-moving stab seem to be fighters or unique, single purpose planes.
As far as your last statement,
But even in the strict sense of the way you use the word, the question of the thread is: once the elevator is in a certain place and your hand is off the stick (aka trimmed), what will the airplane do after disturbances? I.e., what parameter will it tend to maintain? And the answer is it will maintain AOA and therefore airspeed.
Yep! And just remember that the particular FBW laws for your plane move the control surfaces
as required for the commanded gee or AoA or even speed without regard for AoA.
I haven't flown an FBW type with an elevator at the rear end of a stab. So I do not know how the control laws for those decide whether to change the incidence of the stab or crank in some elevator deflection, or both.
Nevertheless, a good discussion. And last I flew, "trimming" was intended to relieve control pressure/movement in order to achieve an attitude or AoA/speed/gee.
Gum sends...