tarn

from WordNet (r) 3.0 (2006)

tarn
    n 1: a mountain lake (especially one formed by glaciers)

from The Collaborative International Dictionary of English v.0.48

Tarn \Tarn\, n. [OE. terne, Icel. tj["o]rn.]
   A mountain lake or pool.
   [1913 Webster]

         A lofty precipice in front,
         A silent tarn below.                     --Wordsworth.
   [1913 Webster]