Definition:Time/Unit/Year

Definition
The year is a derived unit of time.

That is:

It is defined to be equal to the orbital period of Earth round the sun.

Also known as
The year as defined here is also known as a tropical year to distinguish it from the various other types of year.

Also see

 * Definition:Julian Year
 * Definition:Sidereal Year
 * Definition:Civil Year

There are others.