## Wikipedia - Anno (it) year

https://doi.org/10.1351/goldbook.Y06723
Non-SI unit of time, $$\text{a}=31\ 556\ 952\ \text{s}$$. The year is not commensurable with the @D01527@ and not a constant. The value given corresponds to the Gregorian calendar year ($$\text{a}=365.2425\ \text{d}$$).
Source:
Green Book, 2nd ed., p. 111 [Terms] [Book]