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

  • n. The striking of one body against another; collision. See Synonyms at collision.
  • n. The force or impetus transmitted by a collision.
  • n. The effect or impression of one thing on another: still gauging the impact of automation on the lives of factory workers.
  • n. The power of making a strong, immediate impression: a speech that lacked impact.
  • transitive v. To pack firmly together.
  • transitive v. To strike forcefully: meteorites impacting the lunar surface.
  • transitive v. Usage Problem To have an effect or impact on: "No region ... has been more impacted by emerging demographic and economic trends” ( Joel Kotkin).
  • intransitive v. Usage Problem To have an effect or impact.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The force or energy of a collision of two objects.
  • n. A forced impinging.
  • n. A significant or strong influence; an effect.
  • v. To compress; to compact; to press or pack together.
  • v. To influence; to affect; to have an impact on.
  • v. To collide or strike.

from the GNU version of the Collaborative International Dictionary of English

  • n. Contact or impression by touch; collision; forcible contact; force communicated.
  • n. The single instantaneous stroke of a body in motion against another either in motion or at rest.
  • transitive v. To drive close; to press firmly together: to wedge into a place.
  • transitive v. To affect or influence, especially in a significant or undesirable manner.
  • transitive v. To collide forcefully with; to strike.

from The Century Dictionary and Cyclopedia

  • To drive close; press closely or firmly; pack in.
  • n. The act of striking against something; a blow; a stroke.
  • n. Specifically — In mech., the blow, or act of striking, of a body having momentum; also, the change of momentum in amount and direction produced by such a blow.
  • n. In gunnery, the single blow of a projectile against a fixed or moving object.

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

  • v. press or wedge together; pack together
  • n. a forceful consequence; a strong effect
  • n. influencing strongly
  • v. have an effect upon
  • n. the striking of one body against another
  • n. the violent interaction of individuals or groups entering into combat


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

From Latin impāctus, past participle of impingere, to push against; see impinge.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin impāctus, perfect passive participle of impingō ("dash against, impinge").



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  • "In any given perception there is something which has been communicated to it by an impact, or an impression." -Biographia Literaria, 1817

    The word had been used to describe a physical collision since the 1600s, but Coleridge was the first to use it in a metaphorical sense.

    March 5, 2018

  • I've never had a problem differentiating between "affect" and "effect." They are spelled differently and pronounced differently (however slight that difference may seem). Impact as a verb is used primarily by the moderately educated and the pretentious, such as weather forecasters who say things like: "The liquid precipitation will impact your commute tomorrow morning," when they should just tell us that it's going to rain.

    January 1, 2012

  • GlamourGirl, I agree!

    November 16, 2009

  • Using this as both a noun meaning "effect" and verb meaning "affect" avoids the confusion between these two similar words. Maybe this is why it's so popular.

    June 27, 2009

  • I know it's a losing battle by now, but I will never abide this word as a transitive verb. You don't "impact" something, you "affect" it. You can destroy it, tame it, lengthen it, shorten it, kill it, nurture it, hurt it, help it, bend it, build it, or do any number of other things to affect it, but you don't "impact" it!

    June 10, 2009

  • Impact as a verb is unpleasant, brutal, painful. I cringe. My skin crawls.

    May 8, 2009

  • What's the impact this word?

    October 9, 2008

  • This word is used (and misused) in business speak: "that new product will have a big impact on our sales." Or worse: "the change to our commercial will be impactful on our third-quarter sales." Every time I hear the word used this way, I think about impaction of the bowel, and I see that Ninjawords uses that as an example in its definition of the word.

    December 12, 2006