[het″er-ah-del´fus] conjoined twins with one fetus markedly more developed than the other.
het·er·a·del·phus
(het'ĕr-ă-del'fŭs), Unequal conjoined twins in which the smaller incomplete parasite is attached to the larger, more nearly normal autosite. See: conjoined twins. [heter- + G. adelphos, brother]