- something that incites to action or exertion or quickens action, feeling, thought, etc.: The approval of others is a potent stimulus.
- something that excites an organism or part to functional activity.
- something that stimulates or acts as an incentive
- any drug, agent, electrical impulse, or other factor able to cause a response in an organism
- an object or event that is apprehended by the senses
- med a former name for stimulant
