day

The period taken by the earth to make one revolution around its own axis. A day is measured by successive transits of a reference point on the celestial sphere over the meridian, and each type takes its name from the reference used. Thus, for a solar day, the reference is the sun; for a mean solar day, the mean sun; and for an apparent solar day, the apparent sun. For a lunar day, the reference is the moon; for sidereal day, the vernal equinox; and for a constituent day, an astre fictif, or fictitious star. The expression lunar day refers also to the duration of one rotation of the moon with respect to the sun. A mean solar day is equal to 8.64 × 104 s, and a sidereal day is approximately equal to 8.616 × 104 s. A Julian day is from noon, universal time, on the given date to the noon of the following date.

Aviation dictionary. 2014.

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  • day — W1S1 [deı] n ▬▬▬▬▬▬▬ 1¦(24 hours)¦ 2¦(not night)¦ 3¦(when you are awake)¦ 4¦(time at work)¦ 5¦(past)¦ 6¦(now)¦ 7¦(future)¦ 8 somebody s/something s day 9 Independence/election/Christmas etc day 10 five/three/ni …   Dictionary of contemporary English

  • Day — bezeichnet: Day (Sprache), eine Adamaua Sprache Orte in den Vereinigten Staaten: Day (Arkansas) Day Book (North Carolina) Day Center (New York) Day (Florida) Day Heights (Ohio) Day (Kalifornien) Day (Kentucky) Day (Louisiana) Day (Maryland) Day… …   Deutsch Wikipedia

  • day — /day/, n. 1. the interval of light between two successive nights; the time between sunrise and sunset: Since there was no artificial illumination, all activities had to be carried on during the day. 2. the light of day; daylight: The owl sleeps… …   Universalium

  • day — [ deı ] noun *** 1. ) count one of the periods of time that a week is divided into, equal to 24 hours: We re going away for five days. The animals are kept inside for 14 hours a day. 24 hours a day (=during the whole of the day and night): The… …   Usage of the words and phrases in modern English

  • Day — (d[=a]), n. [OE. day, dai, dei, AS. d[ae]g; akin to OS., D., Dan., & Sw. dag, G. tag, Icel. dagr, Goth. dags; cf. Skr. dah (for dhagh ?) to burn. [root]69. Cf. {Dawn}.] 1. The time of light, or interval between one night and the next; the time… …   The Collaborative International Dictionary of English

  • Day — /day/, n. 1. Clarence (Shepard) /shep euhrd/, 1874 1935, U.S. author. 2. Dorothy, 1897 1980, U.S. Roman Catholic social activist, journalist, and publisher. * * * I Time required for a celestial body to turn once on its axis; especially, the… …   Universalium

  • day — [dā] n. [ME dai < OE dæg (pl. dagas), akin to ON dagr, Goth dags, OHG tag < PGmc * dagwaz, prob. < IE base * ag̑hes, day, with d by assoc. with base * dhegwh , to burn] 1. a) the period of light between sunrise and sunset b) daylight c)… …   English World dictionary

  • day — ► NOUN 1) a period of twenty four hours as a unit of time, reckoned from midnight to midnight and corresponding to a rotation of the earth on its axis. 2) the time between sunrise and sunset. 3) (usu. days) a particular period of the past. 4)… …   English terms dictionary

  • day — [n1] light part of every 24 hours astronomical day, bright, dawn to dark, daylight, daytime, diurnal course, early bright, light, light of day, mean solar day, nautical day, sidereal day, sunlight, sunrise to sunset, sunshine, working day;… …   New thesaurus

  • Day 1 — redirects here. For other uses, see Day One (disambiguation). Day 1 Studio album by Robbie Nevil Released …   Wikipedia

  • day — s.m.inv. ES ingl. {{wmetafile0}} giorno in cui si verifica un avvenimento o si celebra una ricorrenza; posposto a un sostantivo e preceduto da un trattino forma lessemi s.m.inv.: compleanno day, matrimonio day, Giampaolo Rossi day {{line}}… …   Dizionario italiano

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