n.1.  A long narrow upper section or crest: the ridge of a wave.
2. a.  A long, narrow, elevated section of the earth's surface, such as a chain of hills or mountains or the divide between adjacent valleys.
b.  A long mountain range on the ocean floor.
 3.  A narrow, elongated zone of relatively high atmospheric pressure. Also called  wedge.
4.  A long, narrow, or crested part of the body: the ridge of the nose.
5.  The horizontal line formed by the juncture of two sloping planes, especially the line formed by the surfaces at the top of a roof.
6.  A narrow, raised strip, as in cloth or on plowed ground.