activate

verb

ac·​ti·​vate ˈak-tə-ˌvāt 

activated; activating

transitive verb

: to make active or more active: such as

a(1)

: to make (something, such as a molecule) reactive or more reactive

(2)

: to convert (something, such as a provitamin) into a biologically active derivative

b

: to make (a substance) radioactive

c

: to treat (a substance, such as carbon or alumina) so as to improve adsorptive properties

d(1)

: to set up or formally institute (an organized group, such as a military unit) with the necessary personnel and equipment

(2)

: to put (an individual or unit) on active duty

intransitive verb

: to become active

activation

ˌak-tə-ˈvā-shən 

noun

activator

ˈak-tə-ˌvā-tər 

noun

Synonyms of activate

• trigger
• spark
• drive
• power
• generate
• move

Examples of activate in a Sentence

Touch the screen to activate the system.

activate and then deactivate a mechanism

The camera is activated by pushing a button.

The bomb was activated by remote control.

Sunlight activates a chemical reaction in the plant's leaves.

vitamins that activate the growth of new cells

The President has activated the reserves.

Recent Examples on the Web

Caffeine seems to activate a cellular system, AMPK, that helps cells sense when energy is low. — Maggie Ryan, Flow Space, 21 Sep. 2026

In the first season’s finale, the MDR team successfully orchestrates a plan to activate their work consciousness in the outside world, hoping to communicate to others the conditions of their confinement. — Jordana Rosenfeld, Encyclopedia Britannica, 21 Sep. 2026

This requirement will roll out broadly next year, but it’s being activated in a few markets in the coming weeks. — ArsTechnica, 21 Sep. 2026

The Miami Dolphins have activated the most experienced, and most inexperienced pass rushers on the roster to address the absence of Chop Robinson for Sunday’s game against the San Francisco 49ers. — Omar Kelly, Miami Herald, 20 Sep. 2026

Word History

Etymology

active entry 1 + -ate entry 4, probably as adaptation of French activer, going back to Middle French, derivative of actif active entry 1

First Known Use

1624, in the meaning defined at transitive sense

Rhymes for activate

• abdicate
• abrogate
• acetate
• actuate
• aggravate
• agitate
• alginate
• alienate
• allocate
• amputate
• angulate
• annotate

Kids Definition

activate

verb

ac·​ti·​vate ˈak-tə-ˌvāt 

activated; activating

1

: to make active

2

: to make (as molecules) more chemically active

3

: to make (a substance) give off radioactive particles, give off light at low temperatures, be easily affected by light, or carry an electric charge under the influence of light or other electromagnetic radiation

4

: to treat (as carbon or alumina) so as to improve the amount of adsorption

5

: to place on active military duty

activate the reserves

activation

ˌak-tə-ˈvā-shən 

noun

activator

ˈak-tə-ˌvāt-ər 

noun

Medical Definition

activate

transitive verb

ac·​ti·​vate ˈak-tə-ˌvāt 

activated; activating

: to make active or more active: as

a

: to convert into a biologically active derivative or form

activated plasminogen

b

: to make biologically or molecularly active

activate protein synthesis

The [spinal] cord also contains neuronal circuits … that can be activated by incoming sensory signals without input from the brain …

—John W. McDonald et al., Scientific American

c

: to make (a substance) radioactive

activation

ˌak-tə-ˈvā-shən 

noun