the word "undershirt" is a transparent compound formed from two old english elements. the first element, "under," originates from proto-germanic under, which itself descends from the proto-indo-european root ndher-, meaning "under." the second element, "shirt," comes from old english scyrte, meaning a short garment or tunic, related to the proto-germanic skurtijǭ and ultimately to the pie root (s)ker-, "to cut." the compound's logic is entirely literal: a shirt worn under another garment. it emerged in the late 16th century, reflecting the practical need to name a specific layer of clothing in the evolving english wardrobe, directly linking the garment's function to its descriptive name.

Structure: under + shirt under: (old english) a preposition/adverb meaning "beneath" or "below," indicating position or location. shirt: (old english) a noun referring to a garment for the upper body, derived from a root meaning "short garment."