a person or thing that retracts. Anatomy. a muscle that retracts an organ or protruded part. Surgery. an instrument or appliance for drawing back an impeding part, as the edge of an incision. a mechanism, device, or the like that regulates retraction: to adjust the retractor on a seat belt.
The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in approximately 27.323 days (a sidereal month). Earth and the Moon orbit about their barycentre (common center of mass), which lies about 4,600 km (2,900 mi) from Earth's center (about 34 of the radius of Earth).
How long is the lunar cycle? In the time it takes for the moon to complete one orbit around Earth, the planet has moved in its orbit around the Sun. It takes the moon approximately 2 days to catch up to Earth's new position relative to the Sun as seen by an observer on Earth.