The Collaborative International Dictionary of English v.0.48:

Bryozoa \Bry`o*zo"a\, n. pl. [NL., fr. Gr. ? moss + ? animal.]
   (Zool.)
   A class of Molluscoidea, including minute animals which by
   budding form compound colonies; -- called also Polyzoa.
   [1913 Webster]

   Note: They are often coralike in form and appearance, each
         small cell containing an individual zooid. Other
         species grow in delicate, flexible, branched forms,
         resembling moss, whence the name. Some are found in
         fresh water, but most are marine. The three principal
         divisions are Ectoprocta, Entoprocta, and
         Pterobranchia. See Cyclostoma, Chilostoma, and
         Phylactolema.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Bryozoa
    n 1: marine or freshwater animals that form colonies of zooids
         [syn: Bryozoa, phylum Bryozoa, polyzoa]