Year
In astronomy, the Julian year is a unit of time; it is defined as 365.25 days of exactly 86,400 seconds (SI base unit), totalling exactly 31,557,600 seconds in the Julian astronomical year.
Mathematical coincidence
Another coincidence related to the gravitational acceleration "g" is that its value of approximately 9.8 m/s is equal to 1.03 light-year/year, which numerical value is close to 1. This is related to the fact that "g" is close to 10 in SI units (m/s), as mentioned above, combined with the fact that the number of seconds per year happens to be close to the numerical value of "c"/10, with "c" the speed of light in m/s. In fact, it has nothing to do with SI as "c/g" = 354 days, nearly, and 365/354 = 1.03.