Exodus 26:17 in the World English Bible
There shall be two tenons in each board, joined to one another: thus you shall make for all the boards of the tabernacle.
Context
16 Ten cubits shall be the length of a board, and a cubit and a half shall be the breadth of one board.
17 Two tenons shall there be in one board, set in order one against another: thus shalt thou make for all the boards of the tabernacle.
18 And thou shalt make the boards for the tabernacle, twenty boards on the south side southward.