Non-SI unit of time, \(\rm{a}=31\ 556\ 952\ \rm{s}\). The year is not commensurable with the
day and not a constant. The value given corresponds to the Gregorian calendar year (\(\rm{a}=365.2425\ \rm{d}\)).
Source:Green Book, 2
nd ed., p. 111 [
Terms] [
Book]