1.NounThe linkage in a (watch) that gives impulses to the timekeeping element and periodically releases the gear train to move forward, advancing the clock's hands.
"The escapement is the reason why clocks tick."
2.NounA mechanism found in devices such as a typewriter or printer which controls lateral motion of the carriage.
3.NounAn escape or a means of escape.
4.NounThe number of fish that escape commercial fishing operations and travel upstream to spawn.