n.

1. time for Earth to make a complete rotation on its axis;
   twenty-four hours, twenty-four hour period, 24-hour interval, solar day, mean solar day
   
   • two days later they left
   • they put on two performances every day
   • there are 30,000 passengers per day
2. some point or period in time
   
   • it should arrive any day now
   • after that day she never trusted him again
   • those were the days
   • these days it is not unusual
3. the time after sunrise and before sunset while it is light outside;
   daytime, daylight
   
   • the dawn turned night into day
   • it is easier to make the repairs in the daytime
4. a day assigned to a particular purpose or observance
   
   • Mother's Day
5. the recurring hours when you are not sleeping (especially those when you are working)
   
   • my day began early this morning
   • it was a busy day on the stock exchange
   • she called it a day and went to bed
6. an era of existence or influence
   
   • in the day of the dinosaurs
   • in the days of the Roman Empire
   • in the days of sailing ships
   • he was a successful pianist in his day
7. a period of opportunity
   
   • he deserves his day in court
   • every dog has his day
8. the period of time taken by a particular planet (e.g. Mars) to make a complete rotation on its axis
   
   • how long is a day on Jupiter?
9. the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day;
   sidereal day
10. United States writer best known for his autobiographical works (1874-1935);
    Day, Clarence Day, Clarence Shepard Day Jr.