groove

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

• noun A long narrow furrow or channel.
• noun The spiral track cut into a phonograph record for the stylus to follow.
• noun Slang A settled routine.
• noun Slang A situation or an activity that one enjoys or to which one is especially well suited.
• noun Slang A very pleasurable experience.
• intransitive verb To cut a groove or grooves in.
• intransitive verb Baseball To throw (a pitch) over the middle of home plate, where it is likely to be hit.
• intransitive verb To take great pleasure or satisfaction; enjoy oneself.
• intransitive verb To be affected with pleasurable excitement.
• intransitive verb To react or interact harmoniously.
• idiom (in the groove) Performing exceptionally well.

from The Century Dictionary.

• To cut or make a groove or channel in; furrow.
• To form as or fix in a groove; make by cutting a groove or grooves.
• noun A pit or hole in the ground; specifically, in mining, a shaft or pit sunk into the earth.
• noun A furrow or long hollow, such as is cut by a tool; a rut or furrow, such as is formed in the ground or in a rock by the action of water; a channel, usually an elongated narrow channel, formed by any agency.
• noun Specifically A long and regular incision cut by a tool, or a narrow channel formed in any way (as in a part of a construction), for something (as another part) to fit into or move in.
• noun Especially— The sunken or plowed channel on the edge of a matched board, to receive the tongue.
• noun The spiral rifling of a gun.
• noun In the wind-chest of an organ, one of the channels or passages into which the wind in admitted by the pallets, and with which the pipes belonging to a given key are directly or indirectly connected. When a given key is struck, its pallet is opened, and the groove filled with compressed air. Whether all the pipes connected with the groove are sounded or not depends on how many stops are drawn. Also grove.
• noun In anatomy and zoology, a natural furrow or longitudinal hollow or impression, especially one which is destined to receive one of the organs in repose: as, the antennal groove; the rostral groove in the Rhynchophora, etc.
• noun Figuratively, a fixed routine; a narrow, unchanging course; a rut: as, life is apt to run in a groove; a groove of thought or of action.

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

• transitive verb To cut a groove or channel in; to form into channels or grooves; to furrow.
• noun A furrow, channel, or long hollow, such as may be formed by cutting, molding, grinding, the wearing force of flowing water, or constant travel; a depressed way; a worn path; a rut.
• noun Hence: The habitual course of life, work, or affairs; fixed routine.
• noun (Mining), Prov. Eng. A shaft or excavation.

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

• noun A long, narrow channel or depression; e.g., such a slot cut into a hard material to provide a location for an engineering component, a tyre groove, or a geological channel or depression.
• noun A fixed routine
• noun The middle of the strike zone in baseball where a pitch is most easily hit
• noun A pronounced, enjoyable rhythm
• verb To cut a groove or channel in; to form into channels or grooves; to furrow.
• verb To create, dance to, or enjoy rhythmic music.

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

• noun (anatomy) any furrow or channel on a bodily structure or part
• verb hollow out in the form of a furrow or groove
• noun a long narrow furrow cut either by a natural process (such as erosion) or by a tool (as e.g. a groove in a phonograph record)
• verb make a groove in, or provide with a groove
• noun a settled and monotonous routine that is hard to escape