swallowtail

plural swallowtails

1. The forked tail of a swallow.
2. Anything, such as a burgee, of a similar forked shape.
3. A type of tailcoat with two long tapering tails.

   It was April 22, 1831, and a young man was walking down Whitehall in the direction of Parliament Street. He wore shepherd's plaid trousers and the swallow-tail coat of the day, with a figured muslin cravat wound about his wide-spread collar.

   1906, Stanley J[ohn] Weyman, chapter I, in Chippinge Borough, New York, N.Y.: McClure, Phillips & Co., →OCLC, page 01

   1 more example

   They have a peculiar style of dress which they wear among themselves, a close-fitting white shirt with black trousers, and a black frock or upper shirt. The women seem to prefer a dress entirely black. On festivals and state occasions they adopt the swallow-tail coat, chimney-pot hat, and their accompaniments, displaying all the absurdity of our European fashionable dress.

   1869, Alfred Russel Wallace, The Malay Archipelago, volume I, London: Macmillan and Co., page 471

4. Any of various butterflies of the family Papilionidae, many of which have a long extension to each hindwing.

   Claudette visit me […] and the biggest, most beautiful black-and-yellow Jamaican swallowtail butterfly follow behind she, like it give us it little blessing.

   2020, Paul Mendez, Rainbow Milk, Dialogue Books (2021), page 8

   1 more example

   Here I obtained the rare and beautiful swallow-tail butterflies, Papilio aenomaus and P. liris; the males of which are quite unlike each other, and belong in fact to distinct sections of the genus, while the females are so much alike that they are undistinguishable on the wing, and to an uneducated eye equally so in the cabinet.

   1869, Alfred Russel Wallace, The Malay Archipelago, volume I, London: Macmillan and Co., page 297