rundlet

noun

1. A small cask of no certain dimensions, which may contain from 3 to 20 gallons.
2. Such a cask of a certain size; its volume used as a measure for liquids, especially wine, usually 18.5 gallons.

   “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.”

3. (obsolete)A partial or secondary umbel.

   “Rundlets roundish, with many equal, bristle-shaped spokes.”