Emily Dickinson Lexicon

PROMPT'ER, n.

1. One that prompts; one that admonishes or incites to action.
2. One that is placed behind the scenes in a play-house, whose business is to assist the speakers when at a loss, by uttering the first words of a sentence or words forgotten; or any person who aids a public speaker when at a loss, by suggesting the next words of his piece. – Pope.