The meaning of "trim" has branched out (as meanings tend to do) to mean not just the mechanism (tab, etc.) that neutralizes the elevator force, but also simply the final elevator+stab position (regardless of what combination of forces put them there) and what effect does that have on the airplane. (Like used in the Stability and Control section of Aerodynamics for Naval Aviators, p. 264)
The effect of elevator deflection on pitching
moments is illustrated by the first graph of
figure 4.13. If the elevators of the airplane are
fixed at zero deflection, the resulting line of
CM versus CL for 0° depicts the static stability
and trim lift coefficient. If the elevators are
fixed at a deflection of 10° up, the airplane
static stability is unchanged but the trim lift
coefficient is increased. A change in elevator
or stabilizer position does not alter the tail
contribution to stability but the change in
pitching moment will alter the lift coefficient
at which equilibrium will occur.
As the ele-
vator is fixed in various positions, equilibrium
(or trim) will occur at various lift coefficients
and the trim CL can be correlated with elevator
deflection as in the second graph of figure 4.13.
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.