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from The American Heritage® Dictionary of the English Language, 4th Edition

  • transitive v. To set in motion; make active or more active.
  • transitive v. To organize or create (a military unit, for example): activate the National Guard.
  • transitive v. To treat (sewage) with aeration and bacteria to aid decomposition.
  • transitive v. Chemistry To accelerate a reaction in, as by heat.
  • transitive v. Physics To make (a substance) radioactive.
  • transitive v. Biology To convert (certain biological compounds) into biologically active derivatives.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • v. To put into action, to put to work.
  • v. To turn on.

from the GNU version of the Collaborative International Dictionary of English

  • transitive v. To make active.

from The Century Dictionary and Cyclopedia

  • To make active; intensify.
  • In physics, to render active; specifically, to make radioactive by exposure to the influence of a radioactive substance; to ionize. See radioactivity.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • v. put in motion or move to act
  • v. make active or more active
  • v. make more adsorptive
  • v. make (substances) radioactive
  • v. aerate (sewage) so as to favor the growth of organisms that decompose organic matter


Sorry, no etymologies found.



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