escapement

noun

1. The 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.”

   “For some reason, adjusting the 400-day clock escapement strikes fear into the hearts of many clock repairers.”

2. A mechanism found in devices such as a typewriter or printer which controls lateral motion of the carriage.
3. An escape or a means of escape.
4. The number of fish that escape commercial fishing operations and travel upstream to spawn.

   “Importantly, there are also extensive practical difficulties associated with gathering and interpreting accurate escapement and run-size information and applying it to population management.”

   “They obtained migration information from a mark– recapture experiment, daily escapement information from aerial surveys, and daily catch information from fish tickets.”

   “Who actually listens to us when we tell him we need to cut back on escapement in the Kanuyaq because too many salmon are getting past the dip netters and it's messing with the spawning beds?”