n (context|military|nautical|navigation) The angle between the magnetic meridian|magnetic and geographic meridian|geographical meridians at any place, expressed in degrees east or west to indicate the direction of magnetic north from true north. In nautical navigation|nautical and aeronautical navigation, the term magnetic variation is used instead of magnetic declination and the angle is termed 'variation of the compass' or magnetic variation. Magnetic declination is not otherwise synonymous with magnetic variation which refers to regular or irregular change with time of the magnetic declination, dip, or intensity'Joint Publication 1-02 U.S. Department of Defense Dictionary of Military and Associated Terms; 12 April 2001 (As Amended Through 14 April 2006).'.