n. (pl. shelves) 1 a a thin flat piece of wood or metal etc. projecting from a wall, or as part of a unit, used to support books etc. b a flat-topped recess in a wall etc. used for supporting objects. 2 a a projecting horizontal ledge in a cliff face etc. b a reef or sandbank under water. c = continental shelf. on the shelf 1 (of a woman) past the age when she might expect to be married. 2 (esp. of a retired person) no longer active or of use. shelf-life the amount of time for which a stored item of food etc. remains usable. shelf-mark a notation on a book showing its place in a library. shelf-room available space on a shelf. shelved adj. shelfful n. (pl. -fuls). shelflike adj.
[ ME f. (M)LG schelf, rel. to OE scylfe partition, scylf crag ]