A year is a time interval approximately equal to the period of the Earth's rotation around the Sun.

There are such years in Astronomy:

1) a sidereal (star) year, corresponding to one visible rotation of the Sun along the celestial sphere has 365,2564 average solar days according to the stable stars;

2) a tropical year is a time interval between the Sun's two centre successive passing through the medium point of the vernal equinox (365,2422 days);

3) anomalistic year is a time interval between the Sun's two centre successive passing through the perihelion of its visible heliocentric orbit (365,2596 days);