borer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A tool used for drilling.
• noun An insect or insect larva, such as a corn borer, that bores chiefly into the stems and trunks of plants.
• noun Any of various mollusks that bore into soft rock or wood.

from The Century Dictionary.

• noun A marine snail, as Urosalpinx cinerca: so named because of its habit of boring through the shells of oysters and other mollusks.
• noun The larva of the American buprestid beetle, Chrysobothris femorata (which see, with cut); the flat-headed apple-tree borer.
• noun The larva of a crambid moth, Diatræa saccharalis, which bores in sugar-cane in the West Indies and the southern United States, where it is also known as the larger corn-stalk borer.
• noun A scolytid beetle, Xyleborus perforans.
• noun The larva of the sugarcane weevil, a calandrid beetle, Sphenophorus obscurus, common in the islands of the Pacific.
• noun One who bores or pierces.
• noun A tool or instrument used for boring; an auger; specifically, in Great Britain, a drill, an implement used in boring holes in rock.
• noun A name common to many minute coleopterous insects of the group Xylophaga, whose larvæ eat their way into old wood, forming at the bottom of the holes a little cocoon, whence they emerge as small beetles.
• noun Some other insect which bores, either in the larval or adult state.
• noun A local English name of the glutinous hag, Myxine glutinosa. See cut under hag.
• noun A bivalve mollusk which bores into wood or stone, especially one of the family Pholadidœ.
• noun In entomology, the terebra or ovipositor when it is used for boring, as in many beetles, flies, etc.

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

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

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

• noun A person who bores, who drills.
• noun A tool used for drilling.
• noun An insect or insect larva that bores into wood.
• noun One of the many types of mollusc that bore into soft rock.
• noun The hagfish (Myxine).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a drill for penetrating rock
• noun any of various insects or larvae or mollusks that bore into wood