An Etymological Dictionary of Astronomy and Astrophysics

A → metric unit of → mass, equal to 1000 → kilograms.

See also: M.E. tunne unit of weight or capacity (cf. O.Fris. tunne, M.Du. tonne, O.H.G. tunna, Ger. tonne), also found in M.L. tunna and O.Fr. tonne, perhaps from a Celtic source.