gooseneck

(often attributive) Anything with a slender curved shape, resembling the neck of a goose, such as the shaft of some lamps.

(nautical) The swivel connection on a sailboat located near the bottom of the mast that the boom attaches to. When a sailboat performs a tack or a jibe the gooseneck swings the boom from one side of the boat to the other.

Short for gooseneck barnacle.