The surface of the moon is rugged with mountains and craters due in part to the absence of eroding forces. Scientists believe the craters were formed when objects traveling in space hit and dented the moon's surface. The seas of the moon are large flat plains called maria. Maria is the latin word for sea. Maria are dry lava beds that were formed by volcanic action on the moon millions of years ago.
Phases refer to the different shapes the moon appears from the earth.
Waxing refers to the moon when it is getting larger or more illuminated from New to Full. Wanning refers to the moon when it is getting smaller or less illuminated from Full to New. Crescent is when the moon is slightly illuminated either before first quarter or after last quarter. Gibbous is when the moon is mostly illuminated either just before or after Full Moon. The moon has no light of its own reflecting the light of the sun.