Definition of activate in English:



  • 1 Make (something) active or operative.

    ‘fumes from cooking are enough to activate the alarm’
    • ‘In Scotland, police were concerned enough to activate a nationwide intelligence centre to evaluate the terrorist threat north of the Border.’
    • ‘When part levels get low at a particular station, the operator activates a radio-frequency signal which causes a paper parts order slip to be generated in the marketplace.’
    • ‘One of the men had climbed through the parcel hatch and told her to keep away from the alarm button but she activated it as they left and saw they had a fourth man as a getaway driver outside.’
    • ‘Last week we had our first serious tornado watch with afternoon skies gone dark enough to activate the street lamps.’
    • ‘Her neighbours rushed in after Mrs Green activated the panic alarm she wears around her neck.’
    • ‘My telescope gathers about 2,000 times as much light as the unaided eye, enough to activate the cone cells in the human retina, so some color appears.’
    • ‘Now, the state has activated its emergency operation center, saying at a level of one to five, it is now at a level of three.’
    • ‘The component also enables the operator to set tolerance limits for important operating parameters, and activates an alarm when deviation from these ranges occurs.’
    • ‘It is almost impossible to deliver an inappropriate shock with an AED because the machine will allow the operator to activate the control only if an appropriate arrhythmia is detected.’
    • ‘But this offering is not enough to activate our intellect.’
    • ‘It's just a simple feedback operation: You click a switch that activates a set of relays that begin feeding electricity back to themselves, so they remain eternally on.’
    • ‘As I was walking back, she saw me and went to roll down the window but hit the door lock by mistake thus activating the car alarm.’
    • ‘Upon the application of Tc, the TetR repressor molecules are released from the tet operators and transcription is activated.’
    • ‘The alarm signal activates the receiver, which then plays the warning to everyone in earshot.’
    • ‘If this is not enough to activate an alliance, what is?’
    • ‘This was the day the GSM operator activated its network and started selling prepaid cards to individual customers.’
    • ‘You'll thereby complete three to six sets per workout, more than enough to activate muscle fibers.’
    • ‘The thieves escaped empty handed after the van's alarm was activated.’
    • ‘Although we could use a lot more rain, most of our fields have had enough to activate the herbicides and early weed control generally has been good.’
    • ‘Although the windows were not linked to the burglar alarm, a sensor activated the system and a passing police patrol stopped to check the building.’
    • ‘It automatically inflates within three to five seconds of immersion in water or can be operated manually by activating a ripcord or by self-inflating.’
    operate, switch on, turn on, start, start off, start up, set going, get going, trigger off, trigger, trip, set in motion, actuate, initiate, initialize, energize, animate
    View synonyms
    1. 1.1Convert (a substance, molecule, etc.) into a reactive form.
      ‘activated chlorine’
      • ‘This messenger in turn activates a so-called kinase, an enzyme that attaches phosphate groups to other proteins.’
      • ‘This results in a decrease in biological activity; but sulphonation is required to activate molecules as well.’
      • ‘This molecule activates enzymes and other substances to help move fat out of fat cells and deliver it to active tissues (such as muscle fibers) that will burn it as fuel.’
      • ‘The specific biochemical reaction to glucagon involves activating a particular enzyme.’
      • ‘The energy that is required to activate molecules for a chemical reaction is the activation energy of the reaction.’