Actual/365
Actual/365, also known as Act/365 and A/365 is a day count fraction. It means the actual number of days in a given calculation period, divided by 365, being the number of days in three out of four years, and so — especially in these low interest times — as near as dammit the number of days in the average year. Punctillious types who would like the exact number of days in any year, including a leap year, are advised to plump for the marginally more accurate actual/actual day count fraction.