Altazimuth, alt-az′i-muth, n. an instrument devised by Sir G. B. Airy for determining the apparent places of the heavenly bodies on the celestial sphere.

The altazimuth can thus determine the altitude and azimuth of objects, hence the name.

This may be furnished either with an equatorial bearing for the telescope, or an altazimuth arrangement which permits both up-and-down and horizontal motions.