short for Conning Officer, the one who, in the absence of the Captain, controls the course and speed of the vessel and as the seniorwatchofficer, is responsible for its safety. Con stands for and is short for control. Whoever is directing the steering of the ship, whether the Captain or the Conning Officer on duty, is said to be "at the con." —Welcome to the SO Glossary Final approval 2-Mar-90