The Collaborative International Dictionary of English v.0.48:

Cue \Cue\ (k[=u]), n. [ OF. coue, coe, F. queue, fr. L. coda,
   cauda, tail. Cf. Caudal, Coward, Queue.]
   1. The tail; the end of a thing; especially, a tail-like
      twist of hair worn at the back of the head; a queue.
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   2. The last words of a play actor's speech, serving as an
      intimation for the next succeeding player to speak; any
      word or words which serve to remind a player to speak or
      to do something; a catchword.
      [1913 Webster]

            When my cue comes, call me, and I will answer.
                                                  --Shak.
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   3. A hint or intimation.
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            Give them [the servants] their cue to attend in two
            lines as he leaves the house.         --Swift.
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   4. The part one has to perform in, or as in, a play.
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            Were it my cueto fight, I should have known it
            Without a prompter.                   --Shak.
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   5. Humor; temper of mind. [Colloq.] --Dickens.
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   6. A straight tapering rod used to impel the balls in playing
      billiards.
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The Collaborative International Dictionary of English v.0.48:

Cue \Cue\, v. t.
   To form into a cue; to braid; to twist.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cue \Cue\, n. [From q, an abbreviation for quadrans a farthing.]
   A small portion of bread or beer; the quantity bought with a
   farthing or half farthing. [Obs.]
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   Note: The term was formerly current in the English
         universities, the letter q being the mark in the
         buttery books to denote such a portion. --Nares.
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               Hast thou worn
               Gowns in the university, tossed logic,
               Sucked philosophy, eat cues?       --Old Play.
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WordNet (r) 3.0 (2006):

cue
    n 1: an actor's line that immediately precedes and serves as a
         reminder for some action or speech
    2: evidence that helps to solve a problem [syn: clue, clew,
       cue]
    3: a stimulus that provides information about what to do [syn:
       discriminative stimulus, cue]
    4: sports implement consisting of a tapering rod used to strike
       a cue ball in pool or billiards [syn: cue, cue stick,
       pool cue, pool stick]
    v 1: assist (somebody acting or reciting) by suggesting the next
         words of something forgotten or imperfectly learned [syn:
         prompt, remind, cue]