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
In cases of near-zero visibility due to dense fog, activate your hazard lights and seek a safe spot, like a nearby business parking lot, to pull over and stop.
—
Nc Weather Bot, Charlotte Observer, 6 Jan. 2026
The system was not activated until her father jumped in after her.
—Nathan Diller, USA Today, 5 Jan. 2026
Padrino did not provide an exact figure for casualties, but endorsed Vice President Delcy Rodríguez's declaration as interim president and said the armed forces have been activated nationwide to guarantee sovereignty.
—Phil Helsel, NBC news, 4 Jan. 2026
Keep your headlights on and activate emergency flashers to alert other drivers of your position.
—Bay Area Weather Report, Mercury News, 4 Jan. 2026
See All Example Sentences for activate
Examples are automatically compiled from online sources to
show current usage.
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Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
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Nc Weather Bot, Charlotte Observer, 6 Jan. 2026
The system was not activated until her father jumped in after her.
—Nathan Diller, USA Today, 5 Jan. 2026
Padrino did not provide an exact figure for casualties, but endorsed Vice President Delcy Rodríguez's declaration as interim president and said the armed forces have been activated nationwide to guarantee sovereignty.
—Phil Helsel, NBC news, 4 Jan. 2026
Keep your headlights on and activate emergency flashers to alert other drivers of your position.
—Bay Area Weather Report, Mercury News, 4 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 8 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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