any of various butterflies of the genus Papilio and related genera, esp P. machaon of Europe, having a tail-like extension of each hind wing: family Papilionidae
2.
the forked tail of a swallow or similar bird
3. short for swallow-tailed coat
Examples of 'swallowtail butterfly' in a sentence
swallowtail butterfly
The caterpillar of a swallowtail butterfly has a false forked tongue: it pretends to be a snake.