Triple Goddess Symbol, composed of waxing crescent, full moon, and waning crescent (filled version).  See Image:Triple-Goddess-Waxing-Full-Waning-Symbol.png for an explanation, or Image:Triple-Goddess-Waxing-Full-Waning-Symbol-multicolored.svg for a version using symbolic colors.
Own work
AnonMoos (first non-vector file version by Switchercat)