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[ak-tuh-veyt] /ˈæk təˌveɪt/
verb (used with object), activated, activating.
to make active; cause to function or act.
  1. to render more reactive; excite:
    to activate a molecule.
  2. to induce radioactivity.
to aerate (sewage) in order to accelerate decomposition of impure organic matter by microorganisms.
  1. to make (carbon, a catalyst, molecules, etc.) more active.
  2. to hasten (reactions) by various means, as heating.
to place (a military unit or station) on an active status in an assigned capacity.
Origin of activate
First recorded in 1620-30; active + -ate1
Related forms
activation, noun
nonactivation, noun
overactivate, verb (used with object), overactivated, overactivating.
superactivate, verb (used with object), superactivated, superactivating.
unactivated, adjective
Can be confused
activate, actuate, stimulate.
1. actuate, start, turn on, set going.
1. stop, halt, check. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for activation
Contemporary Examples
Historical Examples
  • But non-military items also arrived for activation and test.

    The Machine That Saved The World William Fitzgerald Jenkins
  • The scientist set the controls and turned on the activation switch.

    The Golden Skull John Blaine
  • There is no known explanation for this type of activation of the enzyme.

    The Chemistry of Plant Life Roscoe Wilfred Thatcher
  • How this activation is being aided and accelerated by another source of dynamic energy: irradiation from the sun.

    The Brain Alexander Blade
  • It is usually measured by inserting materials of known composition and measuring their activation.

    The Atomic Fingerprint Bernard Keisch
  • Then, as Tony switched the activation circuit, the vertical line formed a pattern that varied in width from top to bottom.

    The Golden Skull John Blaine
  • The activation thereafter had to be done in special equipment permitting of fine control of temperature.

  • activation meant turning them on and giving them a sort of basic training in the tasks they were designed to do.

    The Machine That Saved The World William Fitzgerald Jenkins
British Dictionary definitions for activation


verb (transitive)
to make active or capable of action
(physics) to make radioactive
  1. to increase the rate of (a reaction)
  2. to treat (a substance, such as carbon or alumina) so as to increase powers of adsorption
(physiol) to prepare by arousal (the body or one of its organs (e.g. the brain)) for action
to purify (sewage) by aeration
(US, military) to create, mobilize, or organize (a unit)
Derived Forms
activation, noun
activator, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for activation

1906, noun of action from activate (v.).



1620s; see active + -ate (2). Related: Activated; activating.

Online Etymology Dictionary, © 2010 Douglas Harper
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