orbital period
time taken for a given object to make one complete orbit around another object, and applies in astronomy to mostly either planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars
year
estimated period of time for the Earth's orbit around the Sun and observed at a fixed geographic point (averaging 365.24 days); base later modified to define or adjust various calendars
sidereal period
period is the time required for a celestial body within our solar system to complete one revolution with respect to the fixed stars i.e., as observed from some fixed point outside the system.
synodic period
time between two passes of an object in front of a distant star seen from another orbiting object