We know that a full moon is when the sun is on the other side of us, shining right on the moon, and a new moon is when the moon is totally dark because it is in between the earth and the sun.
Right after a new moon, the moon will start to get some sunlight on it's right side. This makes a crescent shape, so we call it a crescent moon. Since the moon is going to get more full as the days go on, we use the word waxing to say that it is going to get fuller. So we can say the moon is waxing crescent.
(from: wikipedia - category:photographs of the waxing crescent moon)
Kid Facts - Blast from the past: Pluto
