means A garment for the upper body, typically with sleeves, a collar, and a buttoned front, worn against the skin or over an undershirt.

from From Old English 'scyrte,' a cousin of Old Norse 'skyrta' and German 'Schürze' (apron) — all tracing back to a Germanic root meaning 'short,' the same source that gave us 'skirt' (borrowed from Norse). So 'shirt' and 'skirt' are essentially twins, both once meaning a cut-short garment, one settling onto the torso and the other onto the waist.