'Metazoa' definitions:
Definition of 'Metazoa'
(from WordNet)
noun
Multicellular animals having cells differentiated into tissues and organs and usually a digestive cavity and nervous system [syn: Metazoa, subkingdom Metazoa]
Definition of 'Metazoa'
From: GCIDE
- Metazoa \Met`a*zo"a\, n. pl. [NL., fr. Gr. ? after + zo^,on an animal.] (Zool.) Those animals in which the protoplasmic mass, constituting the egg, is converted into a multitude of cells, which are metamorphosed into the tissues of the body. A central cavity is commonly developed, and the cells around it are at first arranged in two layers, -- the ectoderm and endoderm. The group comprises nearly all animals except the Protozoa. [1913 Webster]