#1 impaction n. the condition of being pressed closely together and firmly fixed. wn
#2 impaction n. a disorder in which feces are impacted in the lower colon. wn
#3 impaction n. [impacted tooth] a disorder in which a tooth is so crowded in its socket that it cannot erupt normally. wn
#4 impaction n. [impingement] a sharp collision produced by striking or dashing against something. wn
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