The Collaborative International Dictionary of English v.0.48:

Azimuth \Az"i*muth\, n. [OE. azimut, F. azimut, fr. Ar.
   as-sum?t, pl. of as-samt a way, or perh., a point of the
   horizon and a circle extending to it from the zenith, as
   being the Arabic article: cf. It. azzimutto, Pg. azimuth, and
   Ar. samt-al-r[=a]'s the vertex of the heaven. Cf. Zenith.]
   (Astron. & Geodesy)
      (a) The quadrant of an azimuth circle.
      (b) An arc of the horizon intercepted between the meridian
          of the place and a vertical circle passing through the
          center of any object; as, the azimuth of a star; the
          azimuth or bearing of a line surveying.
          [1913 Webster]

   Note: In trigonometrical surveying, it is customary to reckon
         the azimuth of a line from the south point of the
         horizon around by the west from 0[deg] to 360[deg].
         [1913 Webster]

   Azimuth circle, or Vertical circle, one of the great
      circles of the sphere intersecting each other in the
      zenith and nadir, and cutting the horizon at right angles.
      --Hutton.

   Azimuth compass, a compass resembling the mariner's
      compass, but having the card divided into degrees instead
      of rhumbs, and having vertical sights; used for taking the
      magnetic azimuth of a heavenly body, in order to find, by
      comparison with the true azimuth, the variation of the
      needle.

   Azimuth dial, a dial whose stile or gnomon is at right
      angles to the plane of the horizon. --Hutton.

   Magnetic azimuth, an arc of the horizon, intercepted
      between the vertical circle passing through any object and
      the magnetic meridian. This is found by observing the
      object with an azimuth compass.
      [1913 Webster]

WordNet (r) 3.0 (2006):

azimuth
    n 1: the azimuth of a celestial body is the angle between the
         vertical plane containing it and the plane of the meridian
         [syn: azimuth, AZ]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "azimuth":
   Cartesian coordinates, abscissa, aim, altitude, aspect, attitude,
   bearing, bearings, bent, celestial navigation, compass bearing,
   compass direction, coordinates, course, current,
   cylindrical coordinates, dead reckoning, declination, direction,
   direction line, drift, equator coordinates, exposure,
   false horizon, fix, frontage, heading, helmsmanship, horizon,
   inclination, latitude, lay, lee side, lie, line, line of direction,
   line of march, line of position, longitude, magnetic bearing,
   navigation, ordinate, orientation, pilotage, piloting, point,
   polar coordinates, position, position line, quarter, radio bearing,
   range, relative bearing, right ascension, run, sea line,
   sensible horizon, set, skyline, steerage, steering, tack, tendency,
   tenor, track, trend, true bearing, vector, visible horizon, way,
   weather side