From The Collaborative International Dictionary of English v.0.48 [gcide]:
Impact \Im*pact"\, v. t. [imp. & p. p. Impacted; p. pr. & vb.
n. Impacting.] [L. impactus, p. p. of impingere to push,
strike against. See Impinge.]
1. To drive close; to press firmly together: to wedge into a
place. --Woodward.
[1913 Webster]
2. To affect or influence, especially in a significant or
undesirable manner; as, budget cuts impacted the entire
research program; the fish populations were adversely
impacted by pollution.
[PJC]
3. To collide forcefully with; to strike.
[PJC]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Impact \Im"pact\, n.
1. Contact or impression by touch; collision; forcible
contact; force communicated.
[1913 Webster]
The quarrel, by that impact driven. --Southey.
[1913 Webster]
2. (Mech.) The single instantaneous stroke of a body in
motion against another either in motion or at rest.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
impact
n 1: the striking of one body against another
2: a forceful consequence; a strong effect; "the book had an
important impact on my thinking"; "the book packs a wallop"
[syn: impact, wallop]
3: influencing strongly; "they resented the impingement of
American values on European culture" [syn: impingement,
encroachment, impact]
4: the violent interaction of individuals or groups entering
into combat; "the armies met in the shock of battle" [syn:
shock, impact]
v 1: press or wedge together; pack together
2: have an effect upon; "Will the new rules affect me?" [syn:
affect, impact, bear upon, bear on, touch on,
touch]