Bumkin \Bum"kin\, n. [Boom a beam + -kin. See {Bumpkin}.]
(Naut.)
A projecting beam or boom; as:
(a) One projecting from each bow of a vessel, to haul the
fore tack to, called a tack bumpkin.
(b) One from each quarter, for the main-brace blocks, and
called {brace bumpkin}.
(c) A small outrigger over the stern of a boat, to extend the
mizzen. [Written also {boomkin}.]
[1913 Webster]