borer Meaning, Definition & Usage

  1. noun a drill for penetrating rock
    stone drill; rock drill; bore bit.
  2. noun any of various insects or larvae or mollusks that bore into wood
    woodborer.

WordNet

Bor"er noun
Definitions
  1. One that bores; an instrument for boring.
  2. (Zoöl.) (a) A marine, bivalve mollusk, of the genus Teredo and allies, which burrows in wood. See Teredo. (b) Any bivalve mollusk (Saxicava, Lithodomus, etc.) which bores into limestone and similar substances. (c) One of the larvæ of many species of insects, which penetrate trees, as the apple, peach, pine, etc. See Apple borer, under Apple. (d) The hagfish (Myxine).

Webster 1913