Abarim Publications' online Biblical Greek Dictionary
The noun ιματιον (imation) means piece of clothing and could technically describe any kind of garment. It derives from the more general noun ειμα (eima), which also covers carpets and rugs, and is related to the noun ιμας (imas), which denotes a leather strap with which to tie something upon something else, for instance a helmet onto a head.
Although our noun could describe any piece of clothing, by the time of the New Testament most pieces of under clothing had acquired specific names and our noun ιματιον (imation) began to be used mostly to describe one's outer, most protecting and most exposed garment; the first item that comes off when someone enters a warm and safe place.
Our noun occurs 61 times in the New Testament, see full concordance, and from it derives: