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impact

/ˈɪmpækt//ˈɪmpækt/·noun, verb
the striking of one thing against another; a strong effect
Fig. 1 — It comes down the sky with somewhere to be, and the field receives it all at once: a flash, a ring of shock that leaves the point of contact and goes racing for the edges, dust standing straight up, pebbles hopping where they thought they lived quietly.
01Definition

An impact is first a collision — one body striking another, from Latin impingere, 'to push against' — and then, by the world's favourite metaphor, any strong effect that lands like one: the impact of automation on work, a speech with real impact. The past participle keeps the original physics: an impacted tooth is one wedged hard against its neighbour. As a noun the stress is IM-pact; the verb shifts to im-PACT, and though 'impact' as a verb still annoys some editors, it is standard in news and business English.

02In use
  • iThe meteor's impact left a crater that outlived every mountain range around it.
  • iiCheap credit had a profound impact on how much housing people could chase.
  • iiiPlanting the wetlands again would mitigate the impact of storm tides on the town.
03Collocations
  • have an impact on
  • the impact of
  • environmental impact
  • on impact
  • mitigate the impact

Family impactful (adjective) · impacted (adjective)

04Relations

=collision, blow, shock, effect, influence

06TOEFL & IELTS

One of the highest-value nouns in academic English: 'the impact of X on Y' organises half of IELTS Writing Task 2, and environmental impact is fixed vocabulary in reading passages. Keep the preposition straight — impact ON, never 'impact to' — and keep the stress straight: the noun is IM-pact, the verb im-PACT. In formal writing, 'affect' often reads better than the verb impact, which some style guides still resist; the noun is safe everywhere.

07Asked
What is the difference between impact, affect and effect?
Affect is a verb (the drought affected yields), effect is its noun (the effect on yields), and impact can stand in for either when the influence is strong: a major impact, or, more controversially, 'the drought impacted yields'. The working rule: use affect/effect for ordinary influence and reserve impact for force — if the sentence would survive the meteor strike in the scene above, impact fits.
Is impact a verb?
Yes — and it has been since the 1600s, originally meaning to press or wedge in. What is newer is the figurative use ('the policy impacts families'), which grew through twentieth-century business English and still irritates some editors, who hear jargon where affect would do. Exams will not penalise it, but in formal essays 'affect' or 'influence' is the safer stylistic choice.
Is it impact on or impact to?
Impact ON: the noun takes on for its target — the impact of tourism on coral, a lasting impact on policy. 'Impact to' is a common error worth unlearning. Note the verb takes no preposition at all in standard use: the tax impacts small firms, not 'impacts on' them — though British English tolerates 'impacted on' more than American English does.
How do you pronounce impact — IM-pact or im-PACT?
By part of speech: noun IM-pact, verb im-PACT. English does this initial-stress shift with dozens of noun–verb pairs — record, permit, increase, export — and listening tests quietly rely on your hearing which one was said: catching the stress tells you the grammar before the sentence ends.
What does impacted mean in 'impacted wisdom tooth'?
Wedged — the tooth is pressed hard against its neighbour or the jawbone and cannot come through. Medicine here preserves the word's original, physical sense of being packed tightly in, which predates the metaphorical 'affected'. So an impacted tooth is not a tooth that something influenced; it is a tooth stuck by pressure, true to the Latin root.
Is impactful a real word?
Real, listed in dictionaries, and widely disliked. It has been in print since 1939, but it only became common — and contentious — in recent decades, answering a real need ('having impact'); many editors hear marketing speak and prefer influential, powerful or effective. In IELTS or TOEFL writing it will not cost you marks; in careful academic prose, choosing an established alternative signals better control of register.