activate

American  

[ak-tuh-veyt] / ˈæk təˌveɪt /

verb (used with object)

activated, activating

1. to make active; cause to function or act.

   Synonyms:

   start, actuate

   Antonyms:

   check, halt, stop

2. Physics.

   1. to render more reactive; excite.

      to activate a molecule.

   2. to induce radioactivity.

3. to aerate (sewage) in order to accelerate decomposition of impure organic matter by microorganisms.

4. Chemistry.

   1. to make (carbon, a catalyst, molecules, etc.) more active.

   2. to hasten (reactions) by various means, as heating.

5. to place (a military unit or station) on an active status in an assigned capacity.

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verb (used without object)

activated, activating

1. to become active or functional.

activate British  

/ ˈæktɪˌveɪt /

verb

1. to make active or capable of action

2. physics to make radioactive

3. chem

   1. to increase the rate of (a reaction)

   2. to treat (a substance, such as carbon or alumina) so as to increase powers of adsorption

4. physiol to prepare by arousal (the body or one of its organs (e.g. the brain)) for action

5. to purify (sewage) by aeration

6. military to create, mobilize, or organize (a unit)

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Other Word Forms

• activation
  noun
• activator
  noun
• nonactivation
  noun
• overactivate
  verb (used with object)
• superactivate
  verb (used with object)
• unactivated
  adjective

Etymology

Origin of activate

First recorded in 1620–30; active + -ate ¹

Explanation

To activate something is to start it off, trigger it, or set it in motion. A villain in a late-night movie might say, “Activate the robot chickens!” And then you’re free to activate your remote and change the channel. To activate something is to make it active. It’s not just for bad guys — when you activate a credit or library card, you can start using it. When a coach activates a player on a sports team, the player enters the game. If someone activates a bomb, you should run. If the pancakes you’re cooking burst into flames, you’ll probably activate the smoke alarm. And you should run.

Example Sentences

The most enthusiastic users have even bought programmable foot pedals, a gaming accessory, so they can activate Wispr with their toes.

From The Wall Street Journal • May 10, 2026

The Dodgers plan to activate Snell from the injured list Saturday and start him against the Braves.

From Los Angeles Times • May 9, 2026

It's important to activate the shape-shifting of the energy-storing molecules in a smooth, repeatable way.

From BBC • May 7, 2026

Engineers realized that any further decline could activate the spacecraft's undervoltage fault protection system.

From Science Daily • May 4, 2026

To prevent injury, hold the bag tight as the mojo or juju is released in order to activate the protection mojo.

From "The Manifestor Prophecy" by Angie Thomas

Related Words

• call up
• mobilize
• stimulate
• switch on
• trigger
• turn on