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

• 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

Chinese shares had recently rallied to a multi-year high on expectations of government stimulus and a recent inflow of foreign capital into Chinese equities. —Lee Ying Shan, CNBC, 13 Oct. 2025

Soon after her election, the yen hit a new low amid expectations of major fiscal stimulus. —Hanako Montgomery, CNN Money, 11 Oct. 2025

Surveying 453 dog owners, scientists found that canines’ responses were strongly influenced by the type of stimuli—such as animals or objects—and their watching behavior, whether following the action or remaining still. —Lucy Notarantonio, MSNBC Newsweek, 10 Oct. 2025

Part of what has led to this situation is the cheap money flowing into markets in recent years thanks to the ballooning national debt used to fuel stimulus as well as quantitative easing during the COVID pandemic. —Marco Quiroz-Gutierrez, Fortune, 9 Oct. 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