# activate

/ˈæktəˌveɪt/ (US) · /ˈæktɪvˌeɪt/ (UK)

Source: https://englishreference.com/word/activate
Updated: 2026-06-20

## Senses

### 1. to trigger a device

verb · CEFR B2

to make a machine, alarm, or system start working.

For teachers: to put a device, mechanism, or system into action or motion.

- The smoke from the burnt toast was enough to activate the fire alarm.
- The security system is designed to activate the silent alarm the moment the infrared sensors detect unauthorized movement in the vault.

Usage: This is a transitive verb that always requires a direct object, such as a device or a system.

### 2. to start a process

verb · CEFR B2

to encourage something to develop or to make a process start happening.

For teachers: to induce increased activity or stimulate a specific biological or social process.

- The new government policy aims to activate the local economy by supporting small businesses.
- The enzyme acts as a catalyst to activate the metabolic pathway responsible for breaking down complex sugars during digestion.

### 3. software/computing

verb · CEFR B2

to enter a code or license to make a piece of software fully work.

For teachers: to remove the functional limitations of a software application by providing a valid license key or digital signature.

- You need to connect to the internet to activate your copy of the software.
- Users are prompted to activate their subscription within thirty days to avoid losing access to the cloud-based features of the suite.

### 4. chemistry/physics

verb · CEFR C1 · Technical

to make a substance more reactive or to make it radioactive.

For teachers: to render a molecule or substance reactive, or to induce radioactivity through particle bombardment.

- Heat is often used to activate the chemicals in the mixture.
- The sample was placed inside the reactor core to activate the isotopes for the subsequent medical imaging procedure.

### 5. military/sports

verb · CEFR C1 · Formal

to bring a person or a group into active service or play.

For teachers: to bring a military unit into existence or to return an injured player to an active roster.

- The team decided to activate the star player just before the championship game.
- The department of defense moved to activate several reserve units in response to the escalating border tensions along the border.

## Examples

- You need to enter a code to activate the alarm.
- The bank sent a new credit card, but I have to call them to activate it before use.
- Specialized white blood cells circulate in a dormant state until they encounter specific pathogens that activate their defensive response, triggering a cascade of immune activity throughout the body.

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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.