shelf

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A flat, usually rectangular structure composed of a rigid material, such as wood, glass, or metal, fixed at right angles to a wall or other vertical surface and used to hold or store objects.
2. n. The contents or capacity of such a structure.
3. n. Something, such as a projecting ledge of rock or a balcony, that resembles such a structure.
4. n. A reef, sandbar, or shoal.
5. n. Bedrock.
6. idiom. off the shelf From ready-made merchandise in stock: supplies that were available off the shelf.
7. idiom. on the shelf In a state of disuse.
8. idiom. on the shelf Unemployed.
9. idiom. on the shelf Out of circulation.
10. idiom. on the shelf Retired.

Century Dictionary and Cyclopedia

1. n. A thin slab or plank, a piece of marble, slate, wood, or other material, generally long and narrow, fixed horizontally to a wall, and used for supporting small objects; in general, a narrow flat surface, horizontal or nearly so, and raised above a larger surface, as of a floor or the ground.
2. n. In ship-building, an inner timber, or line of timbers, following the sheer of the vessel, and bolted to the inner side of ribs, to strengthen the frame and sustain the deck-beams. See cut under beam, 3.
3. n. The charging-bed of a furnace.
4. n. In scissors, the bottom of the countersink which receives the head of the screw uniting the two blades
5. Same as shelve.
6. n. A rock, ledge of rocks, reef, or sand-bank in the sea, rendering the water shallow and dangerous to ships; a reef or shoal; a shallow spot.
7. n. A projecting layer or ledge of rock on land.
8. n. The bed-rock; the surface of the bed-rock; the rock first met with after removing or sinking through the superficial detritus.

Wiktionary

1. n. A flat, rigid, rectangular structure, fixed at right angles to a wall, and used to support, store or display objects.
2. n. The capacity of such an object; as, a shelf of videos.
3. n. A projecting ledge that resembles such an object.
4. n. A reef, shoal or sandbar.

GNU Webster's 1913

1. n. (Arch.) A flat tablet or ledge of any material set horizontally at a distance from the floor, to hold objects of use or ornament.
2. n. A sand bank in the sea, or a rock, or ledge of rocks, rendering the water shallow, and dangerous to ships.
3. n. (Mining) A stratum lying in a very even manner; a flat, projecting layer of rock.
4. n. (Naut.) A piece of timber running the whole length of a vessel inside the timberheads.

WordNet 3.0

1. n. a projecting ridge on a mountain or submerged under water
2. n. a support that consists of a horizontal surface for holding objects