Quiz: Remember the definition of mal de mer?
"stage direction," 1550s, from Q, which was used 16c., 17c. in stage plays to indicate actors' entrances, probably as an abbreviation of Latin quando "when" (see quandary) or a similar Latin adverb. Shakespeare has it as both Q and cue.
"billiard stick," 1749, variant of queue (n.). Cue ball first recorded 1881.
1928, from cue (n.1). Related: Cued, cueing.