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);
4) eclipse year is a time interval between the two last Sun's passing through the same (arising or falling) nodal point of the Moon orbit on the ecliptics (346,6200 days) all years duration is given for 1900;
5) calendar year has 365 days for the ordinary years and 366 days for the leap-years;
6) lunar year includes 12 lunar synodic months (about 354, 367 days);