The time between sunrise and sunset. They left the day before yesterday (= two days ago). We're meeting the day after.
Hot by day, cold at night. The meaning of day is the time of light between one night and the next. People sometimes say that they can't wait all day or don't have all day when they are in a hurry and need someone to move or act.
How to use day in a sentence. We'd had this big argument the day before. See examples of day used. The period during the day when there is light from the sun:
The interval of light between two successive nights; The weather did not help; A period of 24 hours, especially from twelve o'clock one night to twelve o'clock the next night…. A period of 24 hours:
Your complete date and time resource. Day is the time when it is light, or the time when you are up and doing things.