Declination of the compass

Declination \Dec`li*na"tion\, n. [L. declinatio a bending aside,
   an avoiding: cf. F. d['e]clination a decadence. See
   {Declension}.]
   1. The act or state of bending downward; inclination; as,
      declination of the head.
      [1913 Webster]

   2. The act or state of falling off or declining from
      excellence or perfection; deterioration; decay; decline.
      "The declination of monarchy." --Bacon.
      [1913 Webster]

            Summer . . . is not looked on as a time
            Of declination or decay.              --Waller.
      [1913 Webster]

   3. The act of deviating or turning aside; oblique motion;
      obliquity; withdrawal.
      [1913 Webster]

            The declination of atoms in their descent.
                                                  --Bentley.
      [1913 Webster]

            Every declination and violation of the rules.
                                                  --South.
      [1913 Webster]

   4. The act or state of declining or refusing; withdrawal;
      refusal; averseness.
      [1913 Webster]

            The queen's declination from marriage. --Stow.
      [1913 Webster]

   5. (Astron.) The angular distance of any object from the
      celestial equator, either northward or southward.
      [1913 Webster]

   6. (Dialing) The arc of the horizon, contained between the
      vertical plane and the prime vertical circle, if reckoned
      from the east or west, or between the meridian and the
      plane, reckoned from the north or south.
      [1913 Webster]

   7. (Gram.) The act of inflecting a word; declension. See
      {Decline}, v. t., 4.
      [1913 Webster]

   {Angle of declination}, the angle made by a descending line,
      or plane, with a horizontal plane.

   {Circle of declination}, a circle parallel to the celestial
      equator.

   {Declination compass} (Physics), a compass arranged for
      finding the declination of the magnetic needle.

   {Declination of the compass} or {Declination of the needle},
      the horizontal angle which the magnetic needle makes with
      the true north-and-south line.
      [1913 Webster]