Cestoidea \Ces*toid"e*a\ (s[e^]s*toid"[-e]*[.a]), n. pl. [NL., gr. Gr. kesto`s girdle + -oid.]

(Zo["o]l.) A class of parasitic worms (Platelminthes) of which the tapeworms are the most common examples. The body is flattened, and usually but not always long, and composed of numerous joints or segments, each of which may contain a complete set of male and female reproductive organs. They have neither mouth nor intestine. See Tapeworm. [Written also Cestoda.]

Source: Webster's Revised Unabridged Dictionary (1913)