Emily Dickinson Lexicon

SWIV-EL, n. [swiv'l; from Sax. swifan, to turn or whirl round; or from the root of whiffle, – which see. In D. weifelen is to palter, to waver, to whiffle.]

1. A ring which turns upon a staple; or a strong link of iron used in mooring ships, and which permits the bridles to be turned round; any ring or staple that turns. – Mar. Dict.
2. A small cannon or piece of artillery, carrying a shot of half a pound, fixed on a socket on the top of a ship's side, stern or bow, or in her tops, in such a manner as to be turned in any direction. – Mar. Dict.