stimulus

American  

[stim-yuh-luhs] / ˈstɪm yə ləs /

noun

plural

stimuli

1. something that incites to action or exertion or quickens action, feeling, thought, etc..

   The approval of others is a potent stimulus.

   Synonyms:

   provocation, motive, enticement, incitement

   Antonyms:

   discouragement

2. Physiology, Medicine/Medical. something that excites an organism or part to functional activity.

   Synonyms:

   stimulant

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stimulus British  

/ ˈstɪmjʊləs /

noun

1. something that stimulates or acts as an incentive

2. any drug, agent, electrical impulse, or other factor able to cause a response in an organism

3. an object or event that is apprehended by the senses

4. med a former name for stimulant

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stimulus Scientific  

/ stĭm′yə-ləs /

plural

stimuli

1. Physiology Something that can elicit or evoke a physiological response in a cell, a tissue, or an organism. A stimulus can be internal or external. Sense organs, such as the ear, and sensory receptors, such as those in the skin, are sensitive to external stimuli such as sound and touch.

2. Something that has an impact or an effect on an organism so that its behavior is modified in a detectable way.

3. See more at classical conditioning

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stimulus Cultural  

1. plur. stimuli (stim-yuh-leye) An action, condition, or person that provokes a response, especially a conditioned response.

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Usage

What does stimulus mean? In general, a stimulus is something that provokes or causes an action or response, as in Failing that test was the stimulus I needed to start studying harder. The plural of stimulus is stimuli. Its verb form is stimulate, which typically means to spur into action or to invigorate. In the context of science, a stimulus is anything that makes an organism or a part of an organism react in some way. For example, for most plants, sunlight acts as a stimulus that causes (stimulates) them to grow or move toward it. In economics, a stimulus is an injection of money into an economy by a government that’s intended to spur (stimulate) economic growth. This can take many forms, such as giving money directly to citizens via stimulus checks. In this sense, stimulus is usually used in the singular, especially in phrases like economic stimulus, stimulus package, and stimulus plan. Example: Congress has passed an unprecedented stimulus package in response to the 2020 coronavirus pandemic in the hopes of stimulating the economy at a time when so many people have lost income due to being out of work.

Other Word Forms

• interstimulus noun
• poststimulus adjective
• prestimulus noun
• understimulus noun

Etymology

Origin of stimulus

First recorded in 1605–15; from Latin: “a goad”

Explanation

A stimulus causes an action or response, like the ringing of your alarm clock if you didn't sleep through it. Stimulus is a word often used in biology — something that causes a reaction in an organ or cell, for example. In financial and economic contexts, a stimulus may be an incentive: the money you spend on your membership is a stimulus for hitting the gym. Though it can be a synonym for stimulant, they are not always used interchangeably. A stimulant is often a chemical or drug that increases activity — think caffeine. For more than one stimulus, use stimuli, not stimuluses.

Example Sentences

Layered on top of this is what bank executives see and feel directly: real stimulus spending and investment vis-à-vis artificial intelligence and other new technology solutions.

From MarketWatch • Apr. 8, 2026

What bankers appear to be calling for is not stimulus or austerity but balance.

From MarketWatch • Apr. 8, 2026

With pandemic-era stimulus initiatives long forgotten, home prices plateauing, and investor portfolios pointing down, consumer sentiment has little reason to improve.

From Barron's • Apr. 2, 2026

Interest-rate futures showed a nearly 80% chance that the Fed would cut rates twice by the end of the year, supporting stocks by offering hope for economic stimulus.

From The Wall Street Journal • Mar. 29, 2026

Bottom-up attention operates unconsciously, automatically, driven by sensory stimulus and contextual cues.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

Related Words

• catalyst
• encouragement
• fillip
• impetus
• incentive
• motivation
• stimulant
• stimulation