Note that "Bosun," spelled that way, is the NATO reporting name for the Soviet Tupolev Tu-14 bomber.

A boatswain (pronounced and often spelt bosun, derived from boat and swain, a servant.) is a warrant officer or petty officer in charge of a ship's anchors, cordage, colours, deck crew and the ship's boats. Onboard a sailing ship such as a man-of-war or a galleon, the boatswain would also be in charge of the rigging while the ship was in dock. It was his duty to summon the crew to work by a whistle.

Onboard merchant vessels, the boatswain is the foreman of the crew, and is sometimes also the third or fourth mate.

Boatswain is also another name for the skua, a predatory bird, though it can be applied to any species of gull of the genus Stercorarius.

Reference

• This article incorporates text from the public domain 1911 Encyclopædia Britannica.