1) British wine 2) Unit of volume 1) Keg 
old liquid measure equal to about 15 gallons
• (n.) A small barrel of no certain dimensions. It may contain from 3 to 20 gallons, but it usually holds about 14/ gallons.
Rund'let noun [ Dim. of Old French rondele a little tun, from rond round. See Round , and confer Roundlet , Runlet .] A small barrel of no certain dimensions. It may contain from 3 to 20 gallons, but it usually holds about 14½ gallons. [ Written also runlet...
an old British measure of capacity, about 15 imperial gallons (68 liters). · a small cask.