—n.
1 a large beer or wine cask.
2 a brewer's fermenting-vat.
3 a measure of capacity, equal to 252 wine gallons.
—v.tr. (tunned, tunning) store (wine etc.) in a tun.
Etymology: OE tunne f. med.L tunna, prob. of Gaulish orig.
Useful english dictionary. 2012.