the.com/cue

The invisible nudge that tells you when to speak, strike, or panic.

means A signal or prompt — an action, word, or object — that tells you the right moment to do something.

from Theatrical in its most traceable sense, cue emerges in the 1500s, likely from 'Q' as a scribal shorthand used in actors' scripts marking where a line began — possibly abbreviating Latin 'quando' ('when'). The billiards cue (the stick) is a totally separate word, from French 'queue,' meaning tail — which is also where the hair-braid and the waiting-line sense of 'queue' come from. English just happened to pile both onto the same sound.

etymology
from Q, shorthand for Latin quando, meaning when
theater origin
stage direction telling actors when to act
billiards twist
same word, different spelling, same idea of precise timing
psychology term
a trigger that prompts automatic behavior or memory
the.com · every word