Justin the 'Cooper" hard at work shaping a cask.
Traditionally, a cooper is someone who makes wooden staved vessels of a conical form, of greater length than breadth, bound together with hoops and possessing flat ends or heads. Examples of a cooper's work include but are not limited to casks, barrels, buckets, tubs, butter churns, hogsheads, firkins, tierces, rundlets, puncheons, pipes, tuns, butts, pins, and breakers. The word is derived from Middle Dutch kūpe, "basket, wood, tub" and may ultimately stem from cupa, the Latin word for vat. Everything a cooper produces is referred to collectively as cooperage. "Cask" is a generic term used to describe any piece of cooperage containing a bouge, bilge, or bulge in the middle of the container...
A barrel is technically a measure of the size of a cask, so the term "barrel-maker" cannot be used synonymously with "cooper." The facility in which casks are made is also referred to as a cooperage.