Tapeworms

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Cestoidea \Ces*toid"e*a\ (s[e^]s*toid"[-e]*[.a]), n. pl. [NL., gr. Gr. kesto`s girdle + -oid.] (Zo["o]l.) same as cestoda ; -- an older usage. [Written also Cestoda .]

Wikipedia Word definitions in Wikipedia
Cestoda ( Cestoidea ) is a class of parasitic flatworms , of the phylum Platyhelminthes . Biologists informally refer to them as cestodes. The best-known species are commonly called tapeworms . All cestodes are parasitic and their life histories vary, but ...