activates; activated; activating
1
: to make (something) active or more active: such as
a
: to cause (a device) to start working
Touch the screen to activate the system.
activate and then deactivate a mechanism
A loud alarm was activated [=set off] when he opened the door.
The camera is activated by pushing a button.
The bomb was activated by remote control.
b
chemistry
: to cause (a chemical reaction or natural process) to begin
Sunlight activates a chemical reaction in the plant's leaves.
vitamins that activate the growth of new cells
2
chiefly US
: to order (soldiers) to serve in a war
The President has activated the reserves.
activate the troops
Our military unit was activated [=called into action] soon after the start of the war.
Cite this Entry
“Activate.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/activate. Accessed 17 Apr. 2026.
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