allantoidoangiopagous twins al·lan·toi·do·an·gi·op·a·gous twins (āl'ən-toi'dō-ān'jē-ŏp'ə-gəs) pl.n. Unequal monozygotic twins with fusion of their allantoic vessels within the placenta. Also called omphaloangiopagous twins.
