What does stimulus mean?
A stimulus is anything that prompts a response or sets some form of action in motion. The word is especially important in biology and psychology, where it describes a physical or sensory event that produces a behavioral or physiological reaction: for example, a flashing light may be a visual stimulus. It is also widely used in economics to describe measures intended to stimulate growth, spending, or investment. More broadly, “stimulus” can refer to anything that prompts creativity, discussion, or further action. Its connotation is generally neutral, though it often suggests an external influence that produces an observable effect. The plural is “stimuli,” and the word is normally used in formal or specialized contexts.
nounSomething that prompts or provokes a response, activity, or reaction. In biology and psychology, it refers especially to an event or condition that causes an organism to respond; in economics, it may refer to measures intended to encourage growth or spending.
- An event, object, or condition that prompts or causes a response.
- In biology and psychology, a physical or sensory event that evokes a behavioral, physiological, or emotional response.
- In economics and public policy, a measure or expenditure intended to encourage activity, investment, or spending.
- Something that prompts thought, creativity, or further action.
"The flashing light acted as a stimulus, prompting the child to respond immediately."
"Noise from the street was the stimulus that woke him up."
"The government introduced tax cuts as an economic stimulus."
“Stimuli” is the standard plural. “Stimulus” is also encountered as a plural in some specialized and scientific contexts.
"The experiment exposed the participants to a series of visual stimuli."
From the Latin word for a goad or spur, “stimulus” has always described something that sets action or reaction in motion.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does stimulus come from?
The English word comes from the Latin noun stimulus, meaning “a goad, spur, or sting,” with related forms such as stimulare, “to stimulate.” In English, its meaning broadened from something that provokes or goads into something that prompts a response. The modern scientific sense developed especially through physiology and psychology, while the economic sense is a later figurative extension.
Related word forms
How stimulus is actually used
The word is formal and especially common in scientific, academic, and economic contexts. In general use, “trigger” may sound more informal, while “stimulus” often suggests a prompt that produces a noticeable response. “Stimuli” is the usual plural; “stimulus” is sometimes used as a plural in specialized writing.
Easily confused with stimulus
A stimulus is something that prompts a response, whereas a stimulant is an agent or substance that produces stimulation, such as caffeine.