means To swallow is to move food, drink, or anything else from your mouth down your throat into your stomach (or, figuratively, to accept something hard to take); the swallow is also a small, swift, fork-tailed migratory bird.

from Both senses trace to Old English, but along separate paths. The verb 'to swallow' comes from Old English 'swelgan,' related to Old High German 'swelgan' and other Germanic words for gulping down. The bird is a different Old English word, 'swealwe,' with cousins in German 'Schwalbe' and Old Norse 'svala' — the two words drifted toward the same spelling by coincidence rather than kinship. So the bird and the gulp are strangers who happen to share a name.