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

Analysts said the persistence of such underlying weakness also raises the question of whether Chinese officials will turn to more fiscal stimulus to try and boost domestic spending. — Stephanie Yang, CNN Money, 15 July 2026

The stutter, in this case, provides a sudden stimulus that triggers the ’keeper to commit to going in a certain direction early, which can then be exploited with a shot sent the other way. — Geir Jordet, New York Times, 14 July 2026

How 40 Hz Sound Therapy Works The treatment is called GENUS, short for gamma entrainment using sensory stimuli. — Samantha Agate, Sacbee.com, 13 July 2026

Chung recently received her first award from the National Institutes of Health for a research project to understand how genetically identical cells respond differently to stimuli, such as treatments or environmental cues. — Rachel Martin, Hartford Courant, 11 July 2026

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