(from Lat. amplus, large), in astronomy, the angular distance of the rising or setting sun, or other heavenly body, from the east or west point of the horizon; used mostly by navigators in finding the variation of the compass by the setting sun. In algebra, if a be a real positive quantity and w a root of unity, then a is the amplitude of the product aw. In elliptic integrals, the amplitude is the limit of integration when the integral is expressed in the form f 4) 1% I - N 2 sin e 4) d4. The hyperbolic or Gudermannian amplitude of the quantity x is ta n (sinh x). In mechanics, the amplitude of a wave is the maximum ordinate.
(See WAVE.)