Swal·low n.
 1. Zool. Any one of numerous species of passerine birds of the family Hirundinidae, especially one of those species in which the tail is deeply forked. They have long, pointed wings, and are noted for the swiftness and gracefulness of their flight.
 Note: ☞ The most common North American species are the barn swallow (see under Barn), the cliff, or eaves, swallow (see under Cliff), the white-bellied, or tree, swallow (Tachycineta bicolor), and the bank swallow (see under Bank). The common European swallow (Chelidon rustica), and the window swallow, or martin (Chelidon urbica), are familiar species.
 2. Zool. Any one of numerous species of swifts which resemble the true swallows in form and habits, as the common American chimney swallow, or swift.
 3. Naut. The aperture in a block through which the rope reeves.
 Swallow plover Zool., any one of several species of fork-tailed ploverlike birds of the genus Glareola, as Glareola orientalis of India; a pratincole.
 Swallow shrike Zool., any one of several species of East Indian and Asiatic birds of the family Artamiidae, allied to the shrikes but similar to swallows in appearance and habits. The ashy swallow shrike (Artamus fuscus) is common in India.
 Swallow warbler Zool., any one of numerous species of East Indian and Australian singing birds of the genus Dicaeum. They are allied to the honeysuckers.