Heading
F5. The Reference Layer: Glossary, Units, Signals and Information SourcesDefinition
Direction in which a vessel's bow is pointing.
Heading is the direction the bow points at an instant, in three-figure degrees, distinct from the course (the intended track over the ground) and the course made good. Heading is read from the steering compass or gyro repeater and differs from course whenever leeway or current sets the vessel off her steered line. A heading is true, magnetic, or compass depending on the reference; the steered compass heading must be corrected for deviation and variation to plot on a true chart.