Two angles are Adjacent when they have a common side and a common vertex (corner point), and don't overlap.
Alternate exterior angles
Alternate interior angles
And they are equal in measure.
the angles that occupy the same relative position at each intersection where a straight line crosses two others. If the two lines are parallel, the corresponding angles are equal.
at an angle of 90° to a given line, plane, or surface. Shows with a small square at the corner of the 90° angle.