In English, we have two main meanings of the word cue. The first is the billiards stick; and the second is the signal to begin an action. Cue is also how we spell the letter Q. Which is important. Remember that. 😉
So our word for the billiards stick or other sporting equipment that bears the same name is actually an anglicized spelling of the French queue. We know that word, of course, because we still use it for “a list” or “a line,” especially in British English. In French the word means “tail,” but you can see the similarity there.
Alright then, what about the second meaning of cue, which we today use far more often? This one is fun. It’s actually where that spelling of the letter comes in–because we in fact, when we use cue for “a signal to begin” mean Q. Short for quando, the Latin word for “when.” That Latin direction was written in the scripts given to individual actors’ partial copies of plays. They didn’t copy the whole things out for everyone, just the line before their own, and then their parts. That line before was marked with quando at first and then abbreviated Q. So the line before your own is your Q … or cue … to begin. We can see this written in original copies of Shakespeare!