From WordNet (r) 3.0 (2006) [wn]:
ledge
n 1: a projecting ridge on a mountain or submerged under water
[syn: ledge, shelf]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Ledge \Ledge\ (l[e^]j), n. [Akin to AS. licgan to lie, Icel.
liggja; cf. Icel. l["o]gg the ledge or rim at the bottom of a
cask. See Lie to be prostrate.] [Formerly written lidge.]
1. A shelf on which articles may be laid; also, that which
resembles such a shelf in form or use, as a projecting
ridge or part, or a molding or edge in joinery.
[1913 Webster]
2. A shelf, ridge, or reef, of rocks.
[1913 Webster]
3. A layer or stratum.
[1913 Webster]
The lowest ledge or row should be of stone. --Sir H.
Wotton.
[1913 Webster]
4. (Mining) A lode; a limited mass of rock bearing valuable
mineral.
[1913 Webster]
5. (Shipbuilding) A piece of timber to support the deck,
placed athwartship between beams.
[1913 Webster]