The terminator is the moving boundary between day and night. Notice that it moves right to left. The moon does not make its own light. We see it because it reflects light from the sun.
Daytime on the moon Night on the moon Terminator
Phases of the moon are caused by the angle between the earth, moon, and sun.
Lunar Phase animation Another animation Video clip on phases Notice that the terminator is moving right to left.
Waxing means getting bigger every night. Waning means getting smaller every night. Crescent means less than half the surface of the moon facing you is lit by the sun. Gibbous means more than half of the surface of the moon facing you is lit by the sun.
Review this diagram and name the phases on the following slides!