Azimuth

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

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.

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.