The horizontal direction of an object or point, usually measured clockwise from a reference line or direction through 360.
A bearing is often designated as true, magnetic, compass, grid, or relative as the reference direction is true, magnetic, compass, or grid north, or heading, respectively.
At one time bearing was restricted to reference to the direction of a terrestrial object or point as distinguished from azimuth which referred to the direction of a celestial body. This distinction has been blurred by usage.
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use