A direction specified as a number of degrees between 001 and 360. The reference is the earth’s magnetic field, and a bearing of 360 degrees magnetic relates to Magnetic North.
Maintain
A word used in an control instruction to a pilot that requires him or her to hold the aircraft at a prescribed altitude
Minimum Vector Altitude
The lowest altitude a Radar Controller is allowed to assign to an aircraft. It is prescribed locally, to provide terrain and obstacle clearance by a specified standard distance and altitude, in conditions under which the pilot is unable to avoid hazards visually. Also called Radar Lowest Safe Altitude.