the phylum of invertebrates comprising the mesozoans, parasitic wormlike multicellular organisms sometimes considered to be intermediate in complexity between protozoans and metazoans.
Main Entry: Me·so·zoa Pronunciation: "mez-&-'zO-&, "mEz-, "mEs-, "mes- Function: noun plural : a phylum or other taxonomic groupcomprising the mesozoans
[mez-uh-zoh-uh, mes-, mee-zuh-, -suh-] 
əˈzoʊ