<p><strong>Noun:</strong></p><ul><li>The tail of a swallow or a deeply forked tail like that of a swallow.</li><li>Any of several butterflies of the genus <em>Papilio</em>, characterized by elongated hindwings that resemble the tail of a swallow, such as <em>P. polyxenes</em> (black swallowtail).</li></ul>