Hair cut straight across the forehead; also refers to loud, sharp sounds or impacts.
From bang meaning 'sudden loud sound' (imitative origin), extended to hair in American English around 1870s, possibly from the abrupt, cut-off appearance. British equivalent is 'fringe.'
The hairstyle 'bangs' got its name because the hair was cut so abruptly it looked like it had been chopped off with a bang - a perfect example of onomatopoeia shaping fashion vocabulary.
Complete word intelligence in one call. Free tier — 50 lookups/day.