AskDefine | Define day

Dictionary Definition

day

Noun

1 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.]

User Contributed Dictionary

English

Etymology

Via < dæġ < < . Not related to Latin dies (< ), but rather to Sanskrit dāhas ‘heat’ < . Cognates include Swedish and Dutch dag and German Tag ‘day’.

Pronunciation

  • , /deɪ/, /deI/
  • Rhymes with: -eɪ

Noun

  1. A period of 24 hours.
  2. The period from midnight to the following midnight. There are 7 days in a week: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday.
  3. Rotational period of a planet (especially earth).
  4. The part of a day period which one spends at one’s job, school, etc.
    • I worked two days last week.
  5. Part of a day period between sunrise and sunset where one enjoys daylight, daytime.
    • day and night.
period of 24 hours
  • Arabic: (yaum)
  • Aramaic:
    Syriac: ܝܘܡܐ (yawmā’)
    Hebrew: יומא (yawmā’)
  • Croatian: dan
  • Czech: den
  • Danish: døgn
  • Dutch: dag, etmaal
  • Esperanto: tago
  • Estonian: ööpäev, päev
  • Ewe: ŋkeke
  • Finnish: päivä, vuorokausi
  • German: Tag
  • Greek: ημέρα (iméra); μέρα (méra); εικοσιτετράωρο (eikositetráoro); ημερονύχτιο (imeroníchtio);
  • Hebrew: יממה (yemama) ; יום (yom)
  • Hungarian: nap
  • Icelandic: dagur
  • Irish: lá
  • Khmer: (tngai)
  • Korean:
  • Kurdish: رۆژ
  • Lao: ວັນ
  • Latin: dies
  • Lithuanian: para
  • Lower Sorbian: źeń
  • Nahuatl: tonalli
  • Norwegian: døgn
  • Old Frisian: di
  • Polish: dzień, doba
  • Portuguese: dia
  • Russian: сутки (sútki) p, день (den’)
  • Serbian:
    Cyrillic: дан
    Roman: dan
  • Slovene: dan
  • Spanish: día
  • Swedish: dygn, dag
  • Tagalog: araw
  • West Frisian: dei
  • Yiddish: טאָג (tog)
period from midnight to the following midnight
  • Aramaic:
    Syriac: ܝܘܡܐ (yawmā’)
    Hebrew: יומא (yawmā’)
  • Chinese:
    Mandarin: (tiān)
  • Croatian: dan
  • Czech: den
  • Danish: døgn, dag
  • Dutch: dag, etmaal
  • Estonian: päev, ööpäev
  • Ewe: ŋkeke
  • Finnish: päivä, vuorokausi
  • German: Tag
  • Greek: ημέρα (iméra); μέρα (méra); εικοσιτετράωρο (eikositetráoro); ημερονύχτιο (imeroníchtio);
  • Hebrew: יממה (yemama) ; יום (yom)
  • Irish: lá
  • Korean: , ,
  • Lao: ວັນ
  • Lower Sorbian: źeń
  • Malay: hari
  • Norwegian: døgn, dag
  • Old Frisian: di
  • Polish: dzień, doba
  • Portuguese: dia
  • Russian: сутки (sútki) p, день (den’)
  • Slovene: dan
  • Swedish: dygn, dag
  • Tagalog: araw
  • West Frisian: dei
rotational period of a planet
  • Chinese:
    Mandarin: (báizhòu)
  • Croatian: dan
  • Danish: døgn
  • Dutch: dag
  • Estonian: päev, ööpäev
  • Ewe: ŋkeke
  • Finnish: vuorokausi
  • German: Tag
  • Greek: ημέρα (iméra); μέρα (méra); εικοσιτετράωρο (eikositetráoro); ημερονύχτιο (imeroníchtio);
  • Irish: lá
  • Malay: hari
  • Norwegian: døgn
  • Polish: dzień
  • Portuguese: dia
  • Russian: сутки (sútki) p, день (d'en’)
  • Slovene: dan
  • Swedish: dygn
part of a day period which one spends at one’s job, school, etc.
  • Chinese:
    Mandarin: (tiān)
  • Croatian: dan
  • Czech: den
  • Danish: dag
  • Dutch: dag
  • Estonian: päev
  • Ewe: ŋkeke
  • Finnish: päivä
  • German: Tag
  • Greek: ημέρα (iméra); μέρα (méra)
  • Hebrew: יום (yom)
  • Irish: lá
  • Korean:
  • Kurdish: رۆژ
  • Malay: hari
  • Norwegian: dag
  • Old Frisian: di
  • Polish: dzień
  • Portuguese: dia
  • Russian: день (d'en’)
  • Slovene: dan
  • Swedish: dag
  • Tagalog: araw
  • West Frisian: dei
period between sunrise and sunset

Scots

Etymology

From dæġ.

Noun

  1. day
  2. (definite singular) today
    • A’m sorry, A’ve no seen Angus the day.
      I’m sorry, I haven’t seen Angus today.

Extensive Definition

A day (symbol: d) is a unit of time equivalent to 24 hours. It is not an SI unit but it is accepted for use with SI. The term comes from the Old English dæg. The word is also used to mean daytime, the period of daylight experienced once per day and alternating with night.

Definitions

The day has several definitions.

International System of Units (SI)

A day contains 86,400 SI seconds. Each second is currently defined as … the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
In the 19th century it had also been suggested to make a decimal fraction ( or ) of an astronomic day the base unit of time. This was an afterglow of the decimal time used with the French Republican Calendar, which had already been given up.

Astronomy

A day of exactly 86,400 SI seconds is the fundamental unit of time in astronomy.
For a given planet, there are two types of day defined in astronomy:: (for Earth it is 23.934 solar hours)

Colloquial

The word refers to various relatedly defined ideas, including the following:
  • The period of light when the Sun is above the local horizon (i.e., the period from sunrise to sunset), opposed to night. See Daytime (astronomy).
  • The full day covering a dark and a light period, beginning from the beginning of the dark period or from a point near the middle of the dark period.
  • A full dark and light period, sometimes called a nychthemeron in English, from the Greek for night-day.
  • The period from 06:00 to 18:00 or 21:00 or some other fixed clock period overlapping or set off from other periods such as "morning", "evening", or "night".
  • The mostly regular interval of one awaking, usually in the morning (personal day).

Introduction

The word day is used for several different units of time based on the rotation of the Earth around its axis. The most important one follows the apparent motion of the Sun across the sky (solar day; see solar time). The reason for this apparent motion is the rotation of the Earth around its axis, as well as the revolution of the Earth in its orbit around the Sun.
A day, as opposed to night, is commonly defined as the period during which sunlight directly reaches the ground, assuming that there are no local obstacles. Two effects make days on average longer than nights. The Sun is not a point, but has an apparent size of about 32 minutes of arc. Additionally, the atmosphere refracts sunlight in such a way that some of it reaches the ground even when the Sun is below the horizon by about 34 minutes of arc. So the first light reaches the ground when the centre of the Sun is still below the horizon by about 50 minutes of arc. The difference in time depends on the angle at which the Sun rises and sets (itself a function of latitude), but amounts to almost seven minutes at least.
Ancient custom has a new day start at either the rising or setting of the Sun on the local horizon (Italian reckoning, for example) The exact moment of, and the interval between, two sunrises or two sunsets depends on the geographical position (longitude as well as latitude), and the time of year. This is the time as indicated by ancient hemispherical sundials.
A more constant day can be defined by the Sun passing through the local meridian, which happens at local noon (upper culmination) or midnight (lower culmination). The exact moment is dependent on the geographical longitude, and to a lesser extent on the time of the year. The length of such a day is nearly constant (24 hours ± 30 seconds). This is the time as indicated by modern sundials.
A further improvement defines a fictitious mean Sun that moves with constant speed along the celestial equator; the speed is the same as the average speed of the real Sun, but this removes the variation over a year as the Earth moves along its orbit around the Sun (due to both its velocity and its axial tilt).
The Earth's day has increased in length over time. The original length of one day, when the Earth was new about 4.5 billion years ago, was about six hours as determined by computer simulation. It was 21.9 hours 620 million years ago as recorded by rhythmites (alternating layers in sandstone). This phenomenon is due to tides raised by the Moon which slow Earth's rotation. Because of the way the second is defined, the mean length of a day is now about 86,400.002 seconds, and is increasing by about 1.7 milliseconds per century (an average over the last 2700 years). See tidal acceleration for details.
During the biblical Creation week, the day appears in several forms: As the seven days in the Creation week ("the evening and the morning", a nychthemeron or 24-hour day), as the light created during the first day ("Let there be light … and God called the light Day" (daylight, not night, Bible verse |Genesis|1:3-5|9), as periods of time delimited by the lights created during the fourth day ("for seasons, and for days, and years", Bible verse |Genesis|1:14|9), and for the Sun created during the fourth day to rule ("the greater light to rule the day", daylight, Bible verse |Genesis|1:16|9).

Civil day

For civil purposes a common clock time has been defined for an entire region based on the mean local solar time at some central meridian. Such time zones began to be adopted about the middle of the 19th century when railroads with regular schedules came into use, with most major countries having adopted them by 1929. For the whole world, 39 such time zones are now in use. The main one is "world time" or UTC (Coordinated Universal Time).
The present common convention has the civil day starting at midnight, which is near the time of the lower culmination of the mean Sun on the central meridian of the time zone. A day is commonly divided into 24 hours of 60 minutes of 60 seconds each.

Leap seconds

The actual mean period of rotation of the earth with respect to the sun is slightly longer than the SI day of 86,400 seconds. It is more nearly 86,400.002 seconds. This additional time accumulates to about 0.7 s per year or about seven seconds every ten years, necessitating the addition of an extra second to the civil clock occasionally to retard it and keep it more closely synchronized to the apparent movement of the sun. By the middle of this century the amount of time to be added to the clock will increase to one second every year. This additional second is called a leap second. A civil clock day is typically 86,400 SI seconds long, but will be 86,401 s or 86,399 s long in the event of a leap second.
Leap seconds are announced in advance by the International Earth Rotation and Reference Systems Service which measures the Earth's rotation and determines whether a leap second is necessary. Leap seconds occur only at the end of a UTC month, and have only ever been inserted at the end of June 30 or December 31.

Astronomy

In astronomy, the sidereal day is also used; it is about 3 minutes 56 seconds shorter than the solar day, and close to the actual rotation period of the Earth, as opposed to the Sun's apparent motion. In fact, the Earth spins 366 times about its axis during a 365-day year, because the Earth's revolution about the Sun removes one apparent turn of the Sun about the Earth.

Boundaries of the day

For most diurnal animals, including Homo sapiens, the day naturally begins at dawn and ends at sunset. Humans, with their cultural norms and scientific knowledge, have supplanted Nature with several different conceptions of the day's boundaries. The Jewish day begins at either sunset or at nightfall (when three second-magnitude stars appear). Medieval Europe followed this tradition, known as Florentine reckoning: in this system, a reference like "two hours into the day" meant two hours after sunset and thus times during the evening need to be shifted back one calendar day in modern reckoning. Days such as Christmas Eve, Halloween, and the Eve of Saint Agnes are the remnants of the older pattern when holidays began the evening before. Present common convention is for the civil day to begin at midnight, that is 00:00 (inclusive), and last a full twenty-four hours until 24:00 (exclusive).
In ancient Egypt, the day was reckoned from sunrise to sunrise. Muslims fast from daybreak to sunset each day of the month of Ramadan. The "Damascus Document", copies of which were also found among the Dead Sea Scrolls, states regarding Sabbath observance that "No one is to do any work on Friday from the moment that the sun's disk stands distant from the horizon by the length of its own diameter," presumably indicating that the monastic community responsible for producing this work counted the day as ending shortly before the sun had begun to set.
In the United States, nights are named after the previous day, e.g. "Friday night" usually means the entire night between Friday and Saturday. This is the opposite of the Jewish pattern. Events starting at midnight are often announced as occurring the day before. TV-guides tend to list nightly programs at the previous day, although programming a VCR requires the strict logic of starting the new day at 00:00 (to further confuse the issue, VCRs set to the 12-hour clock notation will label this "12:00 AM"). Expressions like "today", "yesterday" and "tomorrow" become ambiguous during the night.
Validity of tickets, passes, etc., for a day or a number of days may end at midnight, or closing time, when that is earlier. However, if a service (e.g. public transport) operates from e.g. 6:00 to 1:00 the next day (which may be noted as 25:00), the last hour may well count as being part of the previous day (also for the arrangement of the timetable). For services depending on the day ("closed on Sundays", "does not run on Fridays", etc.) there is a risk of ambiguity. As an example, for the Dutch Railways, a day ticket is valid 28 hours, from 0:00 to 28:00 (i.e. 4:00 the next day). To give another example, the validity of a pass on London Regional Transport services is until the end of the "transport day" -- that is to say, until 4:30 am on the day after the "expiry" date stamped on the pass.

Metaphorical days

In the Bible, as a way to describe that time is immaterial to God, one day is described as being like one thousand years (Psalm 90:4, 2 Peter 3:8) to him. Also in 2 Peter 3:8, one thousand years is described as being like one day. However, some Bible experts interpret this more literally as a way to understand some prophecies like those in Book of Daniel and others (like the Book of Revelation) where are mentioned days in form of weeks and years.

References

See also

day in Afrikaans: Dag
day in Tosk Albanian: Tag
day in Old English (ca. 450-1100): Dæg
day in Arabic: يوم
day in Official Aramaic (700-300 BCE): ܝܘܡܐ
day in Asturian: Día
day in Aymara: Uru
day in Min Nan: Kang
day in Belarusian (Tarashkevitsa): Дзень
day in Bulgarian: Ден
day in Catalan: Dia
day in Chuvash: Кун
day in Czech: Den
day in Welsh: Diwrnod
day in Danish: Dag
day in German: Tag
day in Estonian: Ööpäev
day in Emiliano-Romagnolo: Dè
day in Erzya: Чи (шкань вал)
day in Spanish: Día
day in Esperanto: Tago
day in Basque: Egun
day in Extremaduran: Dia
day in Persian: روز
day in French: Jour
day in Western Frisian: Dei
day in Friulian: Dì
day in Irish: Lá
day in Scottish Gaelic: Là
day in Galician: Día
day in Korean: 날
day in Croatian: Dan
day in Iloko: Aldaw
day in Indonesian: Hari
day in Inuktitut: ᖃᐅ/qau
day in Icelandic: Sólarhringur
day in Italian: Giorno
day in Hebrew: יממה
day in Javanese: Dina
day in Kara-Kalpak: Ku'n (waqıt)
day in Georgian: დღე
day in Kazakh: Күн
day in Swahili (macrolanguage): Siku
day in Haitian: Jou
day in Kurdish: Roj (dem)
day in Ladino: Dia
day in Lao: ມື້
day in Latin: Dies
day in Latvian: Diena
day in Lithuanian: Para
day in Lingala: Mokɔlɔ
day in Lombard: Dí
day in Hungarian: Nap (időegység)
day in Macedonian: Ден
day in Malay (macrolanguage): Hari
day in Mongolian: Өдөр
nah:Tōnalli
day in Dutch: Dag
day in Dutch Low Saxon: Dag
day in Japanese: 日
day in Norwegian: Dag
day in Norwegian Nynorsk: Dag
day in Narom: Jouo
day in Occitan (post 1500): Jorn
day in Low German: Dag
day in Polish: Dzień
day in Portuguese: Dia
day in Romanian: Zi
day in Quechua: P'unchaw
day in Russian: День
day in Albanian: Dita
day in Sicilian: Jornu
day in Simple English: Day
day in Slovenian: Dan
day in Somali: Maalin
day in Serbian: Дан
day in Finnish: Vuorokausi
day in Swedish: Dygn
day in Tagalog: Araw (panahon)
day in Tamil: நாள்
day in Tatar: Kön
day in Thai: วัน
day in Tajik: Рӯз
day in Turkish: Gün
day in Ukrainian: Доба
day in Volapük: Del
day in Võro: Päiv (aomõõt)
day in Yiddish: טאג
day in Yoruba: Ọjọ́
day in Contenese: 一日
day in Samogitian: Dėina
day in Chinese: 日

Synonyms, Antonyms and Related Words

International Date Line, Platonic year, abundant year, academic year, aeon, age, annum, annus magnus, antedate, bissextile year, broad day, calendar month, calendar year, century, common year, cycle, cycle of indiction, date, date line, datemark, dawn, day glow, daylight, dayshine, daytide, daytime, decade, decennary, decennium, defective year, dusk, epoch, era, fateful moment, fiscal year, fortnight, full sun, generation, great year, green flash, heyday, hour, indiction, instant, interval, juncture, kairos, leap year, lifetime, light, light of day, lunar month, lunar year, lunation, luster, lustrum, man-hour, microsecond, midday sun, millennium, millisecond, minute, moment, moment of truth, month, moon, noonlight, noontide light, period, point, point of time, postdate, pregnant moment, prime, psychological moment, quarter, quinquennium, ray of sunshine, regular year, season, second, semester, session, shine, sidereal year, solar year, space, span, spell, stage, stretch, sun, sun spark, sunbeam, sunbreak, sunburst, sunlight, sunshine, term, time, time lag, trimester, twelvemonth, twilight, week, weekday, while, year
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