noun

1. 1. the period of light between sunrise and sunset
   2. daylight
   3. sunshine
2. 1. the 24-hour period (mean solar day) that it takes the earth to rotate once on its axis with respect to the sun: the civil or legal day is from midnight to midnight, the astronomical day from noon to noon
   2. Astron. the time that it takes any celestial body to revolve once on its axis
3. a particular or specified day Memorial Day
4. a period or time; era; age the best writer of her day, in days of old
5. a time of flourishing, power, glory, success, etc. he has had his day
6. the struggle or contest occurring on a certain day they won the day
7. the time one works each day an eight-hour day
8. an unspecified past or future time one of these days
9. one's lifetime; life to spend one's days in study

Etymology: ME dai < OE dæg (pl. dagas), akin to ON dagr, Goth dags, OHG tag < PGmc *dagwaz, prob. < IE base *ahes, day, with d- by assoc. with base *dhegwh-, to burn