What is "day"

Sidereal \Si*de"re*al\, a. [L. sidereus, from sidus, sideris, a constellation, a star. Cf. Sideral, Consider, Desire.]

1. Relating to the stars; starry; astral; as, sidereal astronomy.

2. (Astron.) Measuring by the apparent motion of the stars; designated, marked out, or accompanied, by a return to the same position in respect to the stars; as, the sidereal revolution of a planet; a sidereal day.

   Sidereal clock, day, month, year. See under Clock, Day, etc.

   Sideral time, time as reckoned by sideral days, or, taking the sidereal day as the unit, the time elapsed since a transit of the vernal equinox, reckoned in parts of a sidereal day. This is, strictly, apparent sidereal time, mean sidereal time being reckoned from the transit, not of the true, but of the mean, equinoctial point.

Old English dæg "day," also "lifetime," from Proto-Germanic *dagaz "day" (cognates: Old Saxon, Middle Dutch, Dutch dag, Old Frisian dei, Old High German tag, German Tag, Old Norse dagr, Gothic dags), according to Watkins, from from PIE *agh- (2) "a day" considered as a span of time. He adds that the Germanic initial d- is "of obscure origin."\n

\nNot considered to be related to Latin dies (see diurnal), but rather to Sanskrit dah "to burn," Lithuanian dagas "hot season," Old Prussian dagis "summer." Meaning originally, in English, "the daylight hours;" expanded to mean "the 24-hour period" in late Anglo-Saxon times. The day formerly began at sunset, hence Old English Wodnesniht was what we would call "Tuesday night." Names of the weekdays were not regularly capitalized in English until 17c. Day off first recorded 1883; day-tripper first recorded 1897. The days in nowadays, etc. is a relic of the Old English and Middle English use of the adverbial genitive.

n. 1 Any period of 24 hours. 2 A period from midnight to the following midnight. 3 (lb en astronomy) Rotational period of a planet (especially Earth). 4 The part of a day period which one spends at one’s job, school, etc. vb. (context rare English) To spend a day (in a place).

1. n. time for Earth to make a complete rotation on its axis; "two days later they left"; "they put on two performances every day"; "there are 30,000 passengers per day" [syn: twenty-four hours, solar day, mean solar day]

2. some point or period in time; "it should arrive any day now"; "after that day she never trusted him again"; "those were the days"; "these days it is not unusual"

3. the time after sunrise and before sunset while it is light outside; "the dawn turned night into day"; "it is easier to make the repairs in the daytime" [syn: daytime, daylight] [ant: night]

4. a day assigned to a particular purpose or observance; "Mother's Day"

5. the recurring hours when you are not sleeping (especially those when you are working); "my day began early this morning"; "it was a busy day on the stock exchange"; "she called it a day and went to bed"

6. an era of existence or influence; "in the day of the dinosaurs"; "in the days of the Roman Empire"; "in the days of sailing ships"; "he was a successful pianist in his day"

7. a period of opportunity; "he deserves his day in court"; "every dog has his day"

8. the period of time taken by a particular planet (e.g. Mars) to make a complete rotation on its axis; "how long is a day on Jupiter?"

9. the time for one complete rotation of the earth relative to a particular star, about 4 minutes shorter than a mean solar day [syn: sidereal day]

10. United States writer best known for his autobiographical works (1874-1935) [syn: Clarence Day, Clarence Shepard Day Jr.]

Day, published in 1962, is the third book in a trilogy by Elie Wiesel— Night, Dawn, and Day—describing his experiences and thoughts during and after the Holocaust.

Day is the fictional story of a Holocaust survivor who is struck by a taxicab in New York City. While recovering from his injuries, the character reflects on his relationships and experiences during the Second World War, coming to terms with his survival and the deaths of his family and friends. The book was published in the UK as The Accident.

A day is a unit of temporal measurement for a literal day or epoch of time. Day, DAY or Days may also refer to:

Day is a novel by A. L. Kennedy. It won the novel category and the overall Costa Book of the Year Award in the 2007 Costa Book Awards. The novel is about a man who was a tailgunner in a Lancaster bomber aircraft during World War II. Later, he is an extra in a film about prisoners of war.

Day is a surname. Notable people with the surname Day include:

Day is a marble sculpture by Michelangelo, datable to 1526–31. It is a pair with Night on the tomb of Giuliano de' Medici in the Medici Chapel in San Lorenzo in Florence.

A day is a unit of time. In common usage, it is either an interval equal to 24 hours or daytime, the consecutive period of time during which the Sun is above the horizon. The period of time during which the Earth completes one rotation with respect to the Sun is called a solar day. Several definitions of this universal human concept are used according to context, need and convenience. In 1960, the second was redefined in terms of the orbital motion of the Earth, and was designated the SI base unit of time. The unit of measurement "day", redefined in 1960 as 86 400 SI seconds and symbolized d, is not an SI unit, but is accepted for use with SI. A civil day is usually 86 400 seconds, plus or minus a possible leap second in Coordinated Universal Time (UTC), and occasionally plus or minus an hour in those locations that change from or to daylight saving time. The word day may also refer to a day of the week or to a calendar date, as in answer to the question "On which day?" The life patterns of humans and many other species are related to Earth's solar day and the day-night cycle (see circadian rhythms).

In recent decades the average length of a solar day on Earth has been about 86 400.002 seconds (24.000 000 6 hours) and there are about 365.242 2 solar days in one mean tropical year. Because celestial orbits are not perfectly circular, and thus objects travel at different speeds at various positions in their orbit, a solar day is not the same length of time throughout the orbital year. A day, understood as the span of time it takes for the Earth to make one entire rotation with respect to the celestial background or a distant star (assumed to be fixed), is called a stellar day. This period of rotation is about 4 minutes less than 24 hours (23 hours 56 minutes and 4.1 seconds) and there are about 366.242 2 stellar days in one mean tropical year (one stellar day more than the number of solar days). Mainly due to tidal effects, the Earth's rotational period is not constant, resulting in further minor variations for both solar days and stellar "days". Other planets and moons have stellar and solar days of different lengths to Earth's.

The Day Utility was an automobile manufactured in Detroit, Michigan by the Day Automobile Company from 1911-14. The Day used a four-cylinder, engine and shaft drive. Removal of the rear seat and doors allowed the car to be converted from a five-seater touring car to a light truck in one minute. As a truck, the Day was able to carry up to in a by cargo space. The rear seat could be lifted away by triggering two spring locks. The Day had an advertised price of $950US.

Year

Engine

HP

Wheelbase

1911

4-cylinder

21

1912

4-cylinder

26

1913

4-cylinder

33