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

• boost
• encouragement
• goad
• impetus
• impulse
• incentive
• incitation
• incitement
• instigation
• momentum
• motivation
• provocation
• spur
• stimulant
• yeast

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

Triggered by sensory stimuli such as music, scents and foods, nostalgia has the power to mentally transport us back in time. —Chelsea Reid, The Conversation, 17 June 2025

This psychological process, as first described by Ivan Pavlov, explains how our brains learn to associate unrelated stimuli with specific emotional outcomes. —Mark Travers, Forbes.com, 17 June 2025

But organizers refused, pointing to the $68 million that was expected to be generated Saturday — a shot of stimulus into a sputtering economy witnessing its worst crisis in 40 years. —Paola Flores, Los Angeles Times, 16 June 2025

The second, somewhat more complex task was designed to check if the implant enabled the mice to consciously perceive light—in other words, whether the visual stimuli were properly converted into signals in the right areas of their brains. —ArsTechnica, 12 June 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