Source : Webster's Revised Unabridged Dictionary (1913)

Calypso \Ca*lyp"so\ (k[.a]*l[i^]p"s[-o]), n. [The Latinized
   Greek name of a beautiful nymph.] (Bot.)
   A small and beautiful species of orchid, having a flower
   variegated with purple, pink, and yellow. It grows in cold
   and wet localities in the northern part of the United States.
   The {Calypso borealis} is the only orchid which reaches
   68[deg] N.

Source : WordNet®

calypso
     n 1: rare north temperate bog orchid bearing a solitary white to
          pink flower marked with purple at the tip of an erect
          reddish stalk above 1 basal leaf [syn: {fairy-slipper},
          {Calypso bulbosa}]
     2: (Greek mythology) the sea nymph who detained Odysseus for
        seven years