hun·dred·weight / ˈhəndridˌwāt/ (abbr.: cwt) • n. (pl. same or -weights) a unit of weight equal to one twentieth of a ton, in particular: ∎ (also short hun·dred·weight) (in the U.S.) equal to 100 lb avoirdupois (about 45.4 kg). ∎ (also metric hundredweight) (in the metric system) equal to 50 kg. ∎ (also long hundredweight) (in the UK) equal to 112 lb avoirdupois (about 50.8 kg).