Tongue and groove

Before plywood became common, tongue and groove boards were also used for sheathing buildings and to construct concrete formwork.

[1] In expensive cabinet work, glued dovetail and multiple tongue and groove are used.

For example, plywood flooring is commonly grooved at the edges, and plastic tongues are used to form the joint.

In old sailor slang vernacular, a "tonguin" (pronounced /təŋɪn/) can refer to repairs made to a boat of tongue and groove construction.

A "tonguin" can also refer to a small raft made from tongue and groove construction methods.