a. [f. prec. + -AL 1.]
1. Of or pertaining to the azimuth; used in taking azimuths.
1654. S. Foster (title), Elliptical, or Azimuthal Horologiography.
1667. Phil. Trans., II. 435. The Suns Azimuthal Distance from the Meridian.
1702. Wallis, ibid., XXIII. 1110. The Azimuthal Points of the Horizon.
1841. Brewster, Mart. Sc., III. iv. (1856), 216. A brass azimuthal quadrant.
2. In azimuth, in a horizontal circle. Azimuthal error (of a transit instrument): its deviation in azimuth from the plane of the meridian.
1863. Cornh. Mag., VII. 383. For azimuthal error, that is for the amount that the transit deviates from the north and south line.
1867–77. Chambers, Astron., 668. By means of a screw a small azimuthal motion may be imparted to the instrument.
1880. Nature, XXI. 211/2. The azimuthal rotation of the clouds in Havanna.
