i. The arc of the horizon between the observer’s meridian and the vertical circle of an object, measured either from the north or south, to the right or clockwise, or to the left or counterclockwise, through 90° or 180°. It must be labeled north or south (as a prefix) and east or west (as a prefix) to indicate the direction of measurement.
ii. An angle measured clockwise in the horizontal plane between a reference direction and any other line.
Azimuth angles in both these two cases are 070°.