n. a hardy deciduous American vine (Aristolochia durior) having large, heart-shaped leaves and bearing brownish-purple flowers which have their calyx tubes curved like the bowl of a tobacco pipe. Formerly classified as Aristolochia Sipho. Syn. -- pipe vine, Aristolochia macrophylla, Aristolochia durior. [ 1913 Webster + WordNet 1.5 ]