stim·u·lus | \ ˈstim-yə-ləs \
plural stimuli\ˈstim-yə-ˌlī, -ˌlē \

Definition of stimulus 

: 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)

Keep scrolling for more

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.
See More

Recent Examples on the Web

But the uptick in base rhythm wouldn't mean much because the body is reacting to a stimulus. Jordyn Hermani, Indianapolis Star, "Fishers teen discovers she has heart defect after wearing Fitbit," 14 July 2018 When the brain either reacts to a stimulus spontaneously or decides to form an expression intentionally, a message is sent out over the sixth and seventh cranial nerves. Neil Steinberg, CNN, "How far would you go to be able to smile?," 13 June 2018 University of Cincinnati biology professor Bruce Jayne tells Leahy that a snake’s nervous system can respond to stimulus without needing the brain to send a signal. Meilan Solly, Smithsonian, "Why Rattlesnakes Are Just as Dangerous Dead or Alive," 8 June 2018 In these experiments, sensory neurons became sensitized and fired for longer in response to a stimulus. John Timmer, Ars Technica, "Researchers claim to have transferred a memory between two sea slugs," 16 May 2018 In experiments, participants in the United States and in South Korea who were randomly assigned to an inspirational stimulus (writing about an experience or watching a video) subsequently reported a stronger belief in God. Kevin Lewis,, "Another terrible side effect of traffic," 13 Apr. 2018 There are dogs that tend to be more reactive to stimuli. Jen A. Miller, New York Times, "Out of the Doghouse, Into the Bed," 13 Mar. 2018 Taken together, these bills could add up to a stimulus larger than Barack Obama’s American Recovery and Reinvestment Act. Eric Levitz, Daily Intelligencer, "The GOP Is Embracing Fiscal Irresponsibility. That’s (Probably) for the Best.," 7 Feb. 2018 This software requires some degree of recalibration when a new visitor engages the exhibit because each person’s brain and thought patterns—even in response to the same stimuli—are unique. Larry Greenemeier, Scientific American, "Marvel Comics Gets Inside the Heads of the Avengers," 21 Aug. 2014

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'stimulus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of stimulus

1684, in the meaning defined above

History and Etymology for stimulus


Keep scrolling for more

Learn More about stimulus

Statistics for stimulus

Last Updated

7 Sep 2018

Look-up Popularity

Time Traveler for stimulus

The first known use of stimulus was in 1684

See more words from the same year

Keep scrolling for more

More Definitions for stimulus



English Language Learners Definition of stimulus

: something that causes something else to happen, develop, or become more active

: something that causes a change or a reaction


stim·u·lus | \ ˈsti-myə-ləs \
plural stimuli\-ˌlī, -ˌlē \

Kids Definition of stimulus

1 : something that stirs or urges to action The reward was a stimulus for greater effort.

2 : an influence that acts usually from outside the body to partly change bodily activity (as by exciting a receptor or sense organ) Light, heat, and sound are common physical stimuli.


stim·u·lus | \ ˈstim-yə-ləs \
plural stimuli\-ˌlī, -ˌlē \

Medical Definition of stimulus 

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

Keep scrolling for more

Comments on stimulus

What made you want to look up stimulus? Please tell us where you read or heard it (including the quote, if possible).


the setting in which something occurs

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
True or False

Test your knowledge - and maybe learn something along the way.


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!