Acceleration
The amount the velocity of an object is increased by a force during each second it is acted upon by that force. Acceleration is usually measured and expressed in terms of feet per second, per second (fps²).
Aviation Maintenance Technician Handbook — Powerplant, p. G-1
Also defined in 1 more source
Force involved in overcoming inertia, and which may be defined as a change in velocity per unit of time.