stimulus

noun

stim·​u·​lus ˈstim-yə-ləs 

plural stimuli ˈstim-yə-ˌlī  -ˌlē 

: something that rouses or incites to activity: such as

a

: incentive

b

: stimulant sense 1

c

: an agent (such as an environmental change) that directly influences the activity of a living organism or one of its parts (as by exciting a sensory organ or evoking muscular contraction or glandular secretion)

Synonyms of stimulus

• incentive
• impetus
• encouragement
• motivation

Examples of stimulus in a Sentence

The pay raise was a stimulus for production.

Heat and light are physical stimuli.

The dog responded to the stimulus of the ringing bell.

Recent Examples on the Web

Studies have shown that a single session of exposure therapy can produce measurable neural changes, dampening activity in the brain’s fear network and reorganizing responses to feared stimuli. —Maria Williams, USA Today, 12 Nov. 2025

Back then, there were growing concerns an old squad was showing its age, lacking athleticism and the stimulus to go again. —Jacob Tanswell, New York Times, 10 Nov. 2025

The buildout of data infrastructure tied to artificial intelligence investment, strength of corporate earnings, easier monetary policy and stimulus from the One Big Beautiful Bill, all point to a constructive outlook heading into the end of the year. —Sarah Min, CNBC, 7 Nov. 2025

The salience network, which responds to external stimuli. —Angelica Bottaro, Verywell Health, 6 Nov. 2025

Word History

Etymology

Latin

First Known Use

1684, in the meaning defined above

Rhymes for stimulus

• limulus

Kids Definition

stimulus

noun

stim·​u·​lus ˈstim-yə-ləs 

plural stimuli -ˌlī 

-ˌlē

1

: something that rouses or stirs to action : incentive

2

: something (as an environmental change) that acts to partly change bodily activity (as by exciting a sensory organ)

heat, light, and sound are common physical stimuli

Medical Definition

stimulus

noun

stim·​u·​lus ˈstim-yə-ləs 

plural stimuli -ˌlī  -ˌlē 

1

: stimulant sense 1

2

: an agent (as an environmental change) that directly influences the activity of living protoplasm (as by exciting a sensory organ or evoking muscular contraction or glandular secretion)

a visual stimulus