dawn, daybreak

(French law) One of the days specified in a financial penalty whereby a certain amount of money (measured in units per day) must be paid by a fixed date, any unpaid days resulting in days in prison

man-day (one person's working time)

one day, someday (at unspecified time in the past or future)

during the day, by day

workday / weekday

D-Day (“6 June 1944”) (WWII)

(impersonal) to be daylight

big day (a day on which something significant happens)

(informal) the other day (recently, lately)