Yup. Queue is a line. Cue is a trigger. The cashier can cue the next person in the queue to approach the register.

Even more confusingly, my job frequently shorthands “cue” as “Q” because it is quicker to write in a script. For instance, the script margins will have the stage manager’s notes, which include lighting cues, sound cues, etc… So the stage manager will write something like “Q136 when light switch flipped” if lighting cue 136 needs to fire when the actor flips the light switch. So they can call it at the appropriate time.