\Am"pli*tude\, n. [L. amplitudo, fr. amplus: cf. F.
amplitude. See {Ample}.]
1. State of being ample; extent of surface or space;
   largeness of dimensions; size.
         The cathedral of Lincoln . . . is a magnificent
         structure, proportionable to the amplitude of the
         diocese.                              --Fuller.
2. Largeness, in a figurative sense; breadth; abundance;
   fullness.
   (a) Of extent of capacity or intellectual powers.
       ``Amplitude of mind.'' --Milton. ``Amplitude of
       comprehension.'' --Macaulay.
   (b) Of extent of means or resources. ``Amplitude of
       reward.'' --Bacon.
3. (Astron.)
   (a) The arc of the horizon between the true east or west
       point and the center of the sun, or a star, at its
       rising or setting. At the rising, the amplitude is
       eastern or ortive: at the setting, it is western,
       occiduous, or occasive. It is also northern or
       southern, when north or south of the equator.
   (b) The arc of the horizon between the true east or west
       point and the foot of the vertical circle passing
       through any star or object.
4. (Gun.) The horizontal line which measures the distance to
   which a projectile is thrown; the range.
5. (Physics) The extent of a movement measured from the
   starting point or position of equilibrium; -- applied
   especially to vibratory movements.
6. (math.) An angle upon which the value of some function
   depends; -- a term used more especially in connection with
   elliptic functions.
{Magnetic amplitude}, the angular distance of a heavenly
   body, when on the horizon, from the magnetic east or west
   point as indicated by the compass. The difference between
   the magnetic and the true or astronomical amplitude (see 3
   above) is the ``variation of the compass.''