The Azimuth is the angle at which the needle tip is in the groove of the record.
That angle must be exactly 90 degrees, i.e. the needle tip must be perpendicular between the two groove walls.
Azimuth affects both channel balance and stereo imaging and the final scan distortion. With a correct Azimuth setting, the stylus pressure is evenly distributed on both sides of the groove.
The correct VTA or Vertical Tracking Angle is important when scanning the groove and every element has its preferences, but the norm is that the top of the element housing should be parallel to the plate surface.