WordNet (r) 3.0 (2006):

metasequoia
    n 1: large fast-growing Chinese monoecious tree having flat
         bright-green deciduous leaves and small globular cones;
         commonly cultivated in United States as an ornamental;
         known as a fossil before being discovered in China [syn:
         metasequoia, dawn redwood, Metasequoia
         glyptostrodoides]