Pronunciation: (swol'ō-tāl"),[key] —n. 1. the tail of a swallow or a deeply forked tail like that of a swallow.
2. any of several butterflies of the genus Papilio, characterized by elongated hind wings that resemble the tail of a swallow, as P. polyxenes(black swallowtail). Cf. spicebush swallowtail, tiger swallowtail, zebra swallowtail. 3. See tail coat.