n. - One that bores; an instrument for boring.
n. - A marine, bivalve mollusk, of the genus Teredo and allies, which burrows in wood. See Teredo.
n. - Any bivalve mollusk (Saxicava, Lithodomus, etc.) which bores into limestone and similar substances.
n. - One of the larvae of many species of insects, which penetrate trees, as the apple, peach, pine, etc. See Apple borer, under Apple.
n. - The hagfish (Myxine).