From Arabic 'as-sumūt' (the directions) — a navigational term from Arabic astronomy, part of the vast Arabic contribution to Western science.
The angular direction of a celestial body or point on the Earth's surface, measured clockwise from north along the horizon; in navigation and surveying, the horizontal angle between a reference direction (usually north) and a given line.
From Medieval Latin 'azimuth,' from Arabic 'as-sumūt' (the directions, the ways), plural of 'as-samt' (the direction, the way, the path), from 'al-' (the) + 'samt' (direction, path). The 'az-' in English is a corruption of Arabic 'as-' (the definite article assimilated to the following 's'). The word entered European languages through Arabic astronomical treatises translated in medieval Spain, part
Like 'zenith,' 'nadir,' 'algebra,' 'algorithm,' 'alchemy,' and 'almanac,' the word 'azimuth' is Arabic — a reminder that medieval Islamic astronomers were the most advanced in the world, and European science learned its vocabulary from Arabic treatises translated in twelfth-century Spain.