arete

from WordNet (r) 3.0 (2006)

arete
    n 1: a sharp narrow ridge found in rugged mountains

from The Collaborative International Dictionary of English v.0.48

Arete \A`r[^e]te"\, n. [F., lit., a sharp fish bone, ridge,
   sharp edge, fr. L. arista beard of grain.] (Geog.)
   An acute and rugged crest of a mountain range or a subsidiary
   ridge between two mountain gorges.
   [Webster 1913 Suppl.]