coak

from The Century Dictionary.

• noun In ship carpentry, a projection from the end of a piece of wood or timber fitting into a hole in another piece to join them, or a cylinder or pin let into the ends of both pieces.
• noun Nautical, a square metallic bushing in the central pole of the sheave of a block, through whīch the pin passes.
• See coke.
• In ship carpentry, to unite together, as the ends of two pieces of wood, by means of coaks.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb (Carp.) To unite, as timbers, by means of tenons or dowels in the edges or faces.
• noun See coke, n.
• noun (Carp.) A kind of tenon connecting the face of a scarfed timber with the face of another timber, or a dowel or pin of hard wood or iron uniting timbers.
• noun A metallic bushing or strengthening piece in the center of a wooden block sheave.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a wooden dowel
• noun nautical the brass bearing in the sheave of a block
• verb To unite (timbers etc.) by means of tenons or dowels in the edges or face.