zipper + head. From the leather helmets formerly used by early Canadian armoured crewmen, with a pattern of stitching resembling a zipper. There is also a folk etymology referring to the zippers on armoured-vehicle crew suits (re-purposed flight suits).
1960s–1970s, zipper + head. Used by soldiers during the Korean and Vietnam Wars; multiple theories exist as to the specific origin. One is that if an Asian person was shot in the middle of the forehead with a machine gun, the head would split as if being unzipped; another, that the appearance of tire tracks on a body having been run over by a military Jeep or that of tank tracks resembled a zipper.
Modern English dictionary
Explore and search massive catalog of over 900,000 word meanings.
Word of the Day
Get a curated memorable word every day.
Challenge yourself
Level up your vocabulary by setting personal goals.