c.1600, "press closely into something," from L. impactus
, pp. of impingere
"to push into, dash against" (see impinge
). Originally sense preserved in impacted
teeth (1876). Sense of "strike forcefully against something" first recorded 1916. Figurative sense began with use as a noun (1817, first in Coleridge) meaning "effect of coming into contact with a thing or person."