Merriam-Webster Collegiate Dictionary - day

 noun  Etymology: Middle English, from Old English d?g; akin to Old High German tag ~  Date: before 12th century  1.  a. the time of light between one night and the next  b. ~light 1  c. ~time  2. the period of rotation of a planet (as earth) or a moon on its axis  3. the mean solar ~ of 24 hours beginning at mean midnight  4. a specified ~ or date  5. a specified time or period ; age in grandfather's ~ — often used in plural the old ~s the ~s of sailing ships  6. the conflict or contention of the ~ played hard and won the ~  7. the time established by usage or law for work, school, or business DAY  I. biographical name Clarence Shepard, Jr. 1874-1935 American author  II. biographical name Thomas 1748-1789 English author  III. biographical name William Rufus 1849-1923 American statesman & jurist