Year different from Julian calendar year
Abbreviation
In English, the unit of time for year is commonly abbreviated as "y" or "yr". The symbol "a" is more common in scientific literature, though its exact duration may be inconsistent.
In astronomy, the Julian year is a unit of time defined as 365.25 days of exactly 86,400 seconds (SI base unit), totaling exactly 31,557,600 seconds in the Julian astronomical year. The word year is also used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. Similarly, year can mean the orbital period of any planet; for example, a Martian year and a Venusian year refer to the time those planets take to transit one complete orbit. The term can also be used in reference to any long period or cycle, such as the Great Year.Sothic year
The Sothic year is the heliacal year, the interval between heliacal risings, of the star Sirius. It is currently less than the sidereal year and its duration is very close to the Julian year of 365.25 days.