Emily Dickinson Lexicon

STIM'U-LUS, n. [L. This word may be formed on the root of stem, a shoot.]

1. Literally, a goad; hence, something that rouses the mind or spirits; as, the hope of gain is a powerful stimulus to labor and action.
2. In medicine, that which produces a quickly diffused or transient increase of vital energy and strength of action the circulating system.