the tail of a swallow or a deeply forked tail like that of a swallow.
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).Compare spicebush swallowtail, tiger swallowtail, zebra swallowtail.

Origin of swallowtail

First recorded in 1535–45; swallow2 + tail1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for swallowtail

Historical Examples of swallowtail

  • Old Swallowtail reached the stone-yard and climbed the fence.

    Mary Louise in the Country

    L. Frank Baum (AKA Edith Van Dyne)

  • The Red Star line followed in 1821, and soon after the Swallowtail line.

    Fifth Avenue

    Arthur Bartlett Maurice

  • To the left at one tip of the crescent the flash of Swallowtail Light glowed and died like the fire in a gigantic cigarette.

    The Harbor of Doubt

    Frank Williams

  • Once Swallowtail was passed the voyage had begun, and the lead belonged to any one who could take it.

    The Harbor of Doubt

    Frank Williams

  • I aint in a swallowtail coat, but every one knows me, and they know that Ive been up in the roof tryin to stop a leak.

British Dictionary definitions for swallowtail



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
the forked tail of a swallow or similar bird
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for swallowtail

1540s, of a type of arrowhead, from swallow (n.) + tail (n.). Of a type of butterfly, by 1776; of a type of coat, 1835.

Online Etymology Dictionary, © 2010 Douglas Harper