inflected forms: 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 isactivated by pushing a button. • The bomb was activated by remote control.
1 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.
— activation /ˌæktəˈveɪʃən/ noun [noncount]