On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes. Find out today's date, current time, day of the week, week number, and more. Your complete date and time resource. Details about today's date with count of days, weeks, and months, Sun and Moon cycles, Zodiac signs and holidays. 1. Of or relating to the day. 2. Working during the day: the day nurse. 3. Occurring before nightfall: a day hike. Go to an Art Museum Day is a special day celebrated each year on November 9th. This day invites everyone to explore the fascinating world of art by visiting museums. DAY definition: 1. a period of 24 hours, especially from twelve o'clock one night to twelve o'clock the next night…. Learn more. Find a complete list of today's holidays, unique celebrations, and fun ways to celebrate every day of the year. The meaning of DAY is the time of light between one night and the next. How to use day in a sentence. Cook Something Bold and Pungent Day was created to challenge home cooks to use assertive flavors — fermented fish sauce, blue cheese, preserved lemon, or aged garlic — that most recipes tell you to use sparingly. A day is a 24-hour period, or the length of time it takes the Earth to rotate fully on its axis. There are 365 days in a year, and 31 days in the month of January.