5. The chamber of a canal lock; also, a caisson or a cofferdam.

Coffer dam. (Engin.) See Cofferdam, in the Vocabulary. -- Coffer fish. (Zo÷l.) See Cowfish.

Cof"fer, v. t. 1. To put into a coffer. Bacon.

2. (Mining.) To secure from leaking, as a shaft, by ramming clay behind the masonry or timbering. Raymond.