Definition of "tun"

Again, by 28 Hen. VIII, cap. 14, it is re-enacted that the tun of wine should contain 252 gallons, a butt of Malmsey 126 gallons, a pipe 126 gallons, a tercian or puncheon 84 gallons, a hogshead 63 gallons, a tierce 41 gallons, a barrel 31.5 gallons, a rundlet 18.5 gallons.

1882, James Edwin Thorold Rogers, A History of Agriculture and Prices in England, page 205

He therefore sends you, meeter for your spirit, / This tun of treasure; and, in lieu of this, / Desires you let the dukedoms that you claim / Hear no more of you.

1599, William Shakespeare, “The Life of Henry the Fift”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene ii]

A Tun of Man in thy Large bulk is writ, / But sure thou'rt but a Kilderkin of wit.

1682, John Dryden, Mac Flecknoe, lines 195–196

Strong beer that is brewed in small quantities, and ale, whatever the quantity may be, should be tunned the second day after brewing; and small beer should be tunned as soon as it has fairly taken the yeast

1843, Mary Holland, The Complete Economical Cook, and Frugal Housewife‎, 14th edition, page 407