1942, from naphthenic + palmitic, names of the two acids used in manufacture of the chemical thickening agent. See naphtha. It was used especially in mixture with gasoline to make a kind of inflammabvle jelly used in flame-throwers, incendiary bombs, etc. The verb, "to destroy with napalm," is by 1950, from the noun. Related: Napalmed; napalming.
