# stimuli

/ˈstɪmjəˌɫaɪ/ (US) · /stˈɪmjʊlˌaɪ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/stimuli
Updated: 2026-05-06

## Definition

things that cause a reaction or a change in a person, animal, or plant. You might feel a physical reaction to light or sound, or a mental reaction to a new idea.

For teachers: plural form of 'stimulus'; refers to events or substances that evoke a specific functional reaction in an organ or tissue. Often describes external factors that trigger psychological or physiological responses.

## Examples

- Bright lights are strong stimuli for the eyes.
- Newborn babies respond to various environmental stimuli, such as the sound of a voice or the touch of a hand.
- The experiment measured how the subjects' neural pathways adapted to repeated visual stimuli over a period of several weeks, revealing significant plasticity in the primary visual cortex.

## Pitfalls

- Not "The stimuli was very loud." but "The stimuli were very loud." — Stimuli is the plural form of stimulus; it requires a plural verb.

## Usage notes

- The plural form of 'stimulus'. In scientific contexts, it is treated as a plural noun and takes a plural verb.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.