# reaction

/ɹiˈækʃən/ (US) · /ɹɪˈækʃən/ (UK)

Source: https://englishreference.com/word/reaction
Updated: 2026-06-19

## Senses

### 1. response to an event

noun · CEFR B1

something you say, feel, or do because of something else that happened.

For teachers: a physiological or psychological response to a stimulus or event.

- His first reaction to the news was a look of pure surprise.
- The public reaction to the proposed tax increase was overwhelmingly negative, forcing the local council to reconsider its budget priorities.

### 2. chemical change

noun · CEFR B2 · Technical

a process where two or more substances change into something new.

For teachers: a process involving the rearrangement of the molecular or ionic structure of a substance.

- The chemical reaction caused the liquid to turn bright green.
- The catalyst was added to accelerate the reaction, ensuring that the compound reached stability before the temperature dropped.

### 3. online emoji

noun · CEFR B1 · Informal

an icon or emoji you use to show how you feel about a post on social media.

For teachers: a digital feedback mechanism, typically an emoji, used to express a specific sentiment toward online content.

- She got over fifty heart reactions on her new photo.
- The platform introduced several new reactions, allowing users to express nuanced emotions beyond a simple 'like' button.

### 4. political resistance

noun · CEFR C1 · Academic · Formal

a movement that opposes social or political change.

For teachers: opposition to political or social progress or reform; reactionary policy.

- The new law met with strong reaction from traditional groups.
- The revolution was followed by a period of intense political reaction, as the old elite sought to dismantle the newly established democratic institutions.

## Examples

- His reaction to the news was a big smile.
- The government's sudden policy change caused a strong negative reaction from the public and local business owners.
- While the initial chemical reaction produced a significant amount of heat, the secondary phase required a catalyst to ensure the compound remained stable at room temperature.

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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.