Definitions and Identification of Angles - JSS1 Mathematics Lesson Note

Adjacent Angles: Angles that share a common vertex and a common side, but do not overlap. Example: In the figure below, ∠ABC and ∠CBD are adjacent angles.

Source:(Cuemath.com)

Alternate Angles: Angles that are on opposite sides of a transversal line and are outside the lines it intersects. They are equal when the lines intersected are parallel. Example: In the figure below, ∠1 and ∠5 are alternate angles.

Source:(Cuemath.com)