coop·er 
(kpər)
(kpər)n.
A person who makes or repairs wooden barrels and tubs.
[Middle English couper, from Middle Dutch kūper, from kūpe, basket, tub; see COOP.]
cooper v.
cooper·age n.
cooperHeating dampened staves allows a cooper to bend the staves, giving them the curve needed to construct a barrel.