Pronunciation: (stim'yu-lus), [key]
—pl. -liPronunciation: (-lī"). [key]
1. something that incites to action or exertion or quickens action, feeling, thought, etc.: The approval of others is a potent stimulus.
2. Physiol., Med.something that excites an organism or part to functional activity.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.