order of the day

1. The business to be considered or done by a legislature or other body on a particular day. Often used in the plural.
2. The characteristic or most significant aspect or activity: Volatility is the order of the day in the stock market.

noun

An organized list, as of procedures, activities, or events. agenda, calendar, docket, lineup, program, schedule, timetable. See planned/unplanned.

The prevailing or expected mode, the current agenda, as in Volatility is the order of the day in high-tech stocks, or T-shirts and blue jeans were the order of the day for the picnic. This expression, dating from the late 1600s, originally alluded to the subject of debate in a legislature on a particular day, as well as to specific commands given to troops. Its figurative use dates from the second half of the 1700s.

The noun has one meaning:

Meaning #1: the order of business for an assembly on a given day