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

Example Sentences

When an irritant gets on your skin, a biochemical process activates sensory neurons that make you itchy.

From The Wall Street Journal

Once there, it activates immune responses that are tied to inflammation, loss of nerve cells, and declining cognitive function.

From Science Daily

But for Hernández, prison officials activated a four-man tactical team, paying at least three of them overtime to drive him to the luxury hotel in Manhattan, according to government records and law enforcement sources.

From Salon

To address this need, the team created therapeutic vaccines designed to activate CD8 "killer" T cells, the immune system's most powerful cancer fighting cells.

From Science Daily

The team also tested a compound designed to activate these two receptors.

From Science Daily

Related Words

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