A racial slur referring to people of East Asian descent, coined by US soldiers during the Korean War. There are multiple proposed origins, but the most commonly accepted is that it if enemy Asian soldiers were shot in the head with high-powered weapons, their heads would split as if they had been "unzipped". Another origin could be that when enemy soldiers were ran over by military Jeeps, there would be tire tracks on them that resembled zippers. It's violent origin makes it a particularly derogatory pejorative.
It is often shortened to zip, though zip as a racial pejorative may have separate origins of its own
Coined during the korean war and became widely popular during the vietnam war. Referring to the way the head of an asian enemy tended to split open when shot in the middle of the forehead. This splitting is due to the frontal skull suture found in mongoloid bone structure. massive directed trauma to the forehead will often cause the skull to split along the suture line causing the head to appear as if opened by a zipper.
A racial slur coined by US soldiers during Korean War because if Asians were shot in the head with high-powered weapons, their heads would split as if you unzipped them.