The Collaborative International Dictionary of English v.0.48:

Clarinet \Clar"i*net`\, n. [F. clarinette, dim. of clarine, from
   L. clarus. See Clear, and cf. Clarion.] (Mus.)
   A wind instrument, blown by a single reed, of richer and
   fuller tone than the oboe, which has a double reed. It is the
   leading instrument in a military band.

   Note: [Often improperly called clarionet.]
         [1913 Webster] clarinetist

WordNet (r) 3.0 (2006):

clarinet
    n 1: a single-reed instrument with a straight tube