1. An azimuth (from the pl. form of the Arabic noun "السَّمْت" as-samt, meaning "the direction") is an angular measurement in a spherical coordinate system. The vector from an observer (origin) to a point of interest is projected perpendicularly onto a reference plane; the angle between the projected vector and a reference vector on the reference plane is called the azimuth.
2. The azimuth of a celestial body is the angle between the vertical plane containing it and the plane of the meridian.
https://en.wikipedia.org/wiki/Azimuth (1.); https://www.vocabulary.com/dictionary/nl/azimut (2.)