The tun (Old English: tunne, Latin: tunellus, Medieval Latin: tunna) is an English unit of liquid volume (not weight), used for measuring wine,[1] oil or honey. Typically a large vat or vessel, most often holding 252 wine gallons, but occasionally other sizes (e.g. 256, 240 and 208 gallons) were also used.[2] The modern tun is about 954 litres.
The word tun is etymologically related to the word ton for the unit of mass, the mass of a tun of wine being approximately one long ton, which is 2240 pounds (1016 kg). The spellings "tun" and "ton" were sometimes used interchangeably.[3]
memoirs
was invoked but never defined (see the help page).