The Collaborative International Dictionary
Polyzoon
Polyzoon \Pol`y*zo"["o]n\, n.; pl. Polyzoa. [NL. See Polyzoan.] (Zo["o]l.) One of the individual zooids forming the compound organism of a polyzoan.
Wiktionary
polyzoon
n. (context zoology English) A tiny animal that forms compound colonies.