large vessel or cask, of an oblong form, biggest in the middle, and diminishing towards its two ends, girt about with hoops, and used for stowing several kinds of merchandise for convenience of carriage; as brandy, oil, sugar, skins, hats, &c.

Tun is also the name of a measure. A tun of wine is four hogsheads; of timber, a square of 40 solid feet; and of coals 20 cwt.

Tun is also a certain weight whereby the burden of ships, &c., is estimated.