RhymeZone: knighthead definitions

Definitions of knighthead:

noun: A mitred backing timber which extends the after line of the rabbet in the stem to give extra support to the ends of the planks and the bowsprit.
noun: A bollard or bitt.
noun: Either of two timbers rising from the keel of a sailing ship and supporting the inner end of the bowsprit.

(Definitions from Wiktionary)