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a. The striking of one body against another; collision. See Synonyms at collision.
b. The force transmitted by a collision.
2. The effect or impression of one person or thing on another: still gauging the impact of automation on the lives of factory workers.
v. (ĭm-păkt′, ĭm′păkt′) im·pact·ed, im·pact·ing, im·pacts
1. To pack firmly together.
2. To strike forcefully: meteorites impacting the lunar surface.
3. To have an effect or impact on: "No region ... has been more impacted by emerging ... economic trends" (Joel Kotkin).
To have an effect or impact. See Usage Note below.

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

im·pac′tion n.
Usage Note: Impact in the figurative sense of "a dramatic effect" came under criticism in the 1960s, both as a noun and verb. Complaints that the noun was a pointless hyperbole and a vogue word turned out to be short-lived, and this usage is now is standard: in our 2015 survey, 97 percent of the Usage Panel accepted The program might have a positive impact on our nation's youth. (A similar sentence was accepted by 93 percent of the Panel in 2001.) The verb is a different matter. Many people dislike it because they assume it was converted from the noun in the manner of voguish and bureaucratic words like dialogue and interface, but in fact impact was a verb long before it was a noun—the verb dates from the early 1600s, the noun from the late 1700s. Most of the Panelists still disapprove of the intransitive use of the verb meaning "to have an effect": in our 2015 survey, 78 percent of the Panel (down only slightly from 85 percent in 2001) rejected These policies are impacting on our ability to achieve success. The transitive version was once as vilified, but is gradually becoming more acceptable: in 2015, only 50 percent (down from 80 percent in 2001) rejected The court ruling will impact the education of minority students, and only 39 percent (down from 66 percent in 2001) found the literal sense unacceptable in the sentence Thousands of meteors have impacted the lunar surface. Although resistance to the transitive senses is waning, the intransitive use is still strongly disliked and is best avoided. See Usage Notes at contact, impactful.


(ɪmˈpæk ʃən)

1. an act or instance of impacting.
2. the state of being impacted.
[1730–40; < Late Latin]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.impaction - the condition of being pressed closely together and firmly fixed
condition, status - a state at a particular time; "a condition (or state) of disrepair"; "the current status of the arms negotiations"
2.impaction - a disorder in which feces are impacted in the lower colon
disorder, upset - a physical condition in which there is a disturbance of normal functioning; "the doctor prescribed some medicine for the disorder"; "everyone gets stomach upsets from time to time"
3.impaction - a disorder in which a tooth is so crowded in its socket that it cannot erupt normally
disorder, upset - a physical condition in which there is a disturbance of normal functioning; "the doctor prescribed some medicine for the disorder"; "everyone gets stomach upsets from time to time"
4.impaction - a sharp collision produced by striking or dashing against something
crash, smash - the act of colliding with something; "his crash through the window"; "the fullback's smash into the defensive line"


n. impacción.
1. condición de estar alojado o metido con firmeza en un espacio limitado;
2. impedimento de un órgano o parte.


n impactación f; cerumen — tapón de cerumen; dental — inclusión dentaria; fecal — impactación fecal
References in periodicals archive ?
The rollers are designed with high-carbon steel chisel teeth that are properly spaced to reduce the risk of clogs and impactions.
The system also comes with pre-set programs that minimize setup, exclusive 2D+ technology that helps determine the location of supernumerary teeth, find impactions and apical lesions, or identify the root relationship to the inferior alveolar canal.
Avoid Corncob, shavings, sand, or kitty litter as these can cause impactions and the dust can carry fungus spores and infect the respiratory system.
Cases of foreign body obstructions or gizzard impactions are mainly reported in pet birds and poultry.
Upper Right 1 2 3 4 5 6 7 8 9 10 Upper Left N N N N N N N N N N N N N N N N N N N N Lower Right 32 31 30 29 28 27 26 25 24 23 Lower Left Upper Right 11 12 13 14 15 16 Upper Left N N N N N N N N N N N N Lower Right 22 21 20 19 18 17 Lower Left N=Natural tooth, no filling # 17 and # 32 Horizontal impactions
48%, respectively, (5) and is now considered the imaging method of choice for diagnosis of fish bone impactions.
The worst job I ever had: Being the "Girl Friday" nurses' aide at a nursing home where I got donuts and coffee for the nurses every day, emptied bedpans, and checked patients for fecal impactions.
7-9) Laboratory abnormalities associated with impactions are nonspecific.
For three years, the woman had been unable to move her upper and lower extremities voluntarily, so she had a urinary catheter and was subject to frequent fecal impactions.
When these baby teeth are overretained--when they are not shed on schedule--the result can be harmful cross-bite positions or impactions, which can become difficult orthodontic therapeutic challenges in a person with special needs.
Researchers found that 22% of spasmodic (gas) colics were associated with tapeworms, along with 81% of ileal impactions.
Some dogs will have recurrent anal sac impactions or abscesses.