activate

American  

[ak-tuh-veyt] / ˈæk təˌveɪt /

verb (used with object)

• activates,
  present (3rd person singular)
• activated,
  past participle,  past
• activating
  present participle

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)

• activates,
  present (3rd person singular)
• activated,
  past participle,  past
• activating
  present participle

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

Derived Forms

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

Inflected Forms

Participles

• activating
  present
• activated
  past

Conjugated Forms

Present

• activate
  simple
• activates
  simple
• have activated
  perfect
• has activated
  perfect
• am activating
  progressive
• are activating
  progressive
• is activating
  progressive
• have been activating
  perfect progressive
• has been activating
  perfect progressive

Past

• activated
  simple
• had activated
  perfect
• was activating
  progressive
• were activating
  progressive
• had been activating
  perfect progressive

Future

• will activate
  simple
• will have activated
  perfect
• will be activating
  progressive
• will have been activating
  perfect progressive

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

See Examples For:

activate activates activated activating

In a more positive development, Will Smith faced live pitching for the first time since June, and Roberts said that the plan is to activate the catcher during the first week of September.

From Los Angeles Times ● Aug. 22, 2026

They aren’t living drab or depressing lives when the Guardians of the Universe activate them — they’re faring pretty well, all things considered.

From Salon ● Aug. 16, 2026

The protein helps activate many of the genes required for heart cells to develop and function.

From Science Daily ● Aug. 13, 2026

He returns to the club after eight years in England, following PSG's decision to activate a £8.5m release clause in his contract.

From BBC ● Aug. 9, 2026

They activate and silence genes, thereby defining the embryo’s axis from head to tail.

From "The Gene" by Siddhartha Mukherjee

Keytruda is administered at the same time to help make sure the patient’s immune response activates against the leftover cancer cells.

From MarketWatch ● Aug. 20, 2026

But the illness brought on by the worms, and the stirring awareness of her mortality, activates what Ms. Day calls a “coup of the primordial.”

From The Wall Street Journal ● Jul. 29, 2026

Once growth hormone is released, it activates neurons in the locus coeruleus, a brainstem region involved in alertness, attention, thinking, and responding to new experiences.

From Science Daily ● Jul. 5, 2026

They would simply make unmistakably clear that the executive cannot determine whether Congress’ statutory commands ever become operative by controlling the very event that activates them.

From Slate ● Jun. 26, 2026

The move activates his armguards—an enormous, glowing blue shield bursts outward from them in a circle, arcing protectively in front of us both.

From "Warcross" by Marie Lu

Roberts didn’t rule out the possibility of Rushing being activated as a designated hitter down the line.

From Los Angeles Times ● Aug. 22, 2026

Rather than being suppressed by semaglutide, the AgRP neurons were activated.

From Science Daily ● Aug. 20, 2026

Poland's military command said it had mobilised aircraft and activated air defences aimed at protecting its airspace, particularly in areas bordering Ukraine.

From Barron's ● Aug. 20, 2026

The digital bank posted on X, external it had "identified some issues" and activated a stand-in backup service which meant users could still make transactions like card payments and sending and receiving bank transfers.

From BBC ● Aug. 19, 2026

The robot activated her headlights—click—and light beamed out from her eyes.

From "The Wild Robot Protects" by Peter Brown

In animal models, the therapy slowed the growth of pancreatic tumors by selectively activating T cells that fight cancer.

From Science Daily ● Aug. 19, 2026

Cambridge researchers have uncovered why both activating and blocking the same brain receptor can promote weight loss.

From Science Daily ● Aug. 15, 2026

More time is devoted to setting up the dramatic situation than to activating it.

From Los Angeles Times ● Jun. 19, 2026

Summit’s drug, a so-called bispecific antibody, aims to evolve that strategy by activating the immune system while simultaneously starving the tumor.

From The Wall Street Journal ● Jun. 6, 2026

The sublimity of self-sacrifice activating the Cheerleaders overwhelmed him.

From "Travels with Charley in Search of America" by John Steinbeck

Related Words

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