What is The process of one revolution?

If you are talking about bodies in the solar system, then revolution almost always refers to the orbiting motion of a body around another body. This is the motion that gives us the year on earth. The earth revolves around the sun once in about 365.25 days. Revolution can be a little more complex than this. A sidereal revolution is the orbit of a body as it is observed from the distant stars. Synodic revolution is a revolution as it is observed from the body being orbited, and it brings the orbiting body back to its starting point relative to the sun. These two orbital periods are not the same length. The phases of the moon follow the synodic period; the synodic period is longer than the sidereal period by roughly a day or two.