1. prompter - Noun
2. prompter - Adjective
One who, or that which, prompts; one who admonishes or incites to action.
One who reminds another, as an actor or an orator, of the words to be spoken next; specifically, one employed for this purpose in a theater.
Source: Webster's dictionaryAccording to Dianne Zagrodney Ball before the first show, “Our prompter Sue Calder commented after the dress rehearsal, ‘That was our worst one ever.’ Source: Internet
What they don’t know is that they are the actors on the stage; he, the preacher, is merely the prompter standing in the wings reminding them of their lost lines. Source: Internet