Merriam-Webster's Collegiate® Dictionary, 11th Edition
BANG
I. verb
Etymology: probably of Scandinavian origin; akin to Old Norse bang hammering
Date: circa 1550
transitive verb to strike sharply ; bump , to knock, hit, or thrust vigorously often with a sharp noise , to have sexual intercourse with, intransitive verb to strike with a sharp noise or thump, to produce a sharp often metallic explosive or percussive noise or series of such noises, to play a sport (as basketball) in a very aggressive and forceful manner ,
II. noun
Date: circa 1550
a resounding blow, a sudden loud noise,
3. a sudden striking effect, a quick burst of energy , thrill ,
III. adverb
Date: 1828
right , directly ,
IV. noun
Etymology: probably short for bangtail short tail
Date: 1878
a fringe of banged hair,
V. transitive verb
Date: 1878
to cut (as front hair) short and squarely across