deɪ ˈdeɪlaɪt ˈdeɪtaɪm a period of opportunity he deserves his day in court every dog has his day a 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 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 time for Earth to make a complete rotation on its axis two days later they left they put on two performances every day there are 30,000 passengers per day a day assigned to a particular purpose or observance Mother's Day the time after sunrise and before sunset while it is light outside the dawn turned night into day it is easier to make the repairs in the daytime the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day 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? 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