What is the term used for the direction of travel line on the compass?

The term used for the direction of travel line on the compass is commonly referred to as "heading." This term indicates the direction in which a diver (or any navigator) is traveling at any given moment, relative to a specific reference point, usually true north or magnetic north. It's crucial in scuba diving for navigation purposes, as it allows divers to follow a specific route, find their way back to the entry point, or reach a specific dive site effectively.

While "bearing" also pertains to direction, it usually refers to the angle or direction from a specific point to another, which can differ from the immediate direction of travel. "Lubber," on the other hand, is the term for the line marked on a compass that indicates the direction you are currently facing, while "reference" is more general and doesn't specifically address the directional aspect on a compass. Understanding these terminology differences is essential for effective underwater navigation and orientation.