Wordnet 3.0
NOUN (1)
1. 
 one of four subclasses or superorders of Monocotyledones; 
 comprises about 19,000 species in 25 families of mostly terrestrial herbs especially of moist places including: Cyperaceae; 
 Gramineae; 
 Bromeliaceae; 
 and Zingiberaceae; 
[syn: Commelinidae, subclass Commelinidae]
WordNet (r) 3.0 (2006):
Commelinidae
    n 1: one of four subclasses or superorders of Monocotyledones;
         comprises about 19,000 species in 25 families of mostly
         terrestrial herbs especially of moist places including:
         Cyperaceae; Gramineae; Bromeliaceae; and Zingiberaceae
         [syn: Commelinidae, subclass Commelinidae]