a. 1. Having a tail like that of a swallow; hence, like a swallow's tail in form; having narrow and tapering or pointed skirts; as, a swallow-tailed coat. [ 1913 Webster ]

2. (Carp.) United by dovetailing; dovetailed. [ 1913 Webster ]

Swallow-tailed duck (Zool.), the old squaw. --
Swallow-tailed gull (Zool.), an Arctic gull (Xema furcata), which has a deeply forked tail. --
Swallow-tailed hawk or
Swallow-tailed kite (Zool.), the fork-tailed kite. --
Swallow-tailed moth (Zool.), a European moth (Urapteryx sambucaria) having tail-like lobes on the hind wings. [ 1913 Webster ]