activate
verb
ac·ti·vate
ˈak-tə-ˌvāt 
activated; activating
: 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
: to become active
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
Denver activated the undrafted rookie before the postseason.
—
Lance Reynolds, Boston Herald, 25 Jan. 2026
The governors of New York, New Jersey and Connecticut declared states of emergency ahead of the snowstorm, activating emergency protocols and warning people to stay off the roads, which could also become icy as the storm progresses in subfreezing temperatures.
—January 25, CBS News, 25 Jan. 2026
Missile and drone attacks targeted the Ukrainian capital, according to the country’s air force, which activated air defenses.
—Jessie Yeung, CNN Money, 24 Jan. 2026
When the autonomic nervous system is not activated, emotionally secure people reduce the perception of threat, both in themselves and in the person across from them.
—Mark Travers, Forbes.com, 24 Jan. 2026
See All Example Sentences for activate
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Lance Reynolds, Boston Herald, 25 Jan. 2026
The governors of New York, New Jersey and Connecticut declared states of emergency ahead of the snowstorm, activating emergency protocols and warning people to stay off the roads, which could also become icy as the storm progresses in subfreezing temperatures.
—January 25, CBS News, 25 Jan. 2026
Missile and drone attacks targeted the Ukrainian capital, according to the country’s air force, which activated air defenses.
—Jessie Yeung, CNN Money, 24 Jan. 2026
When the autonomic nervous system is not activated, emotionally secure people reduce the perception of threat, both in themselves and in the person across from them.
—Mark Travers, Forbes.com, 24 Jan. 2026
See All Example Sentences for activate
Cite this Entry
“Activate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/activate. Accessed 26 Jan. 2026.
Copy CitationKids 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
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
John W. McDonald et al., Scientific American
c
: to make (a substance) radioactive
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