AskDefine | Define days

Dictionary Definition

days n : the time during which someone's life continues; "the monarch's last days"; "in his final years" [syn: years]

User Contributed Dictionary



  • /ˈdeɪz/, /"deIz/
  • Rhymes with: -eɪz
  • Homophones: daze


days plural
  1. Plural of day
  2. life
    That's how he ended his days.


plural of days
(idiomatic) life
  • German: Tage


  1. During the day.
    She works days at the garage.


during the day
  • German: tagsüber
  • Hungarian: nappal



  1. Plural of day

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.


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.


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)


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).


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.


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.


See also

days in Afrikaans: Dag
days in Tosk Albanian: Tag
days in Old English (ca. 450-1100): Dæg
days in Arabic: يوم
days in Official Aramaic (700-300 BCE): ܝܘܡܐ
days in Asturian: Día
days in Aymara: Uru
days in Min Nan: Kang
days in Belarusian (Tarashkevitsa): Дзень
days in Bulgarian: Ден
days in Catalan: Dia
days in Chuvash: Кун
days in Czech: Den
days in Welsh: Diwrnod
days in Danish: Dag
days in German: Tag
days in Estonian: Ööpäev
days in Emiliano-Romagnolo: Dè
days in Erzya: Чи (шкань вал)
days in Spanish: Día
days in Esperanto: Tago
days in Basque: Egun
days in Extremaduran: Dia
days in Persian: روز
days in French: Jour
days in Western Frisian: Dei
days in Friulian: Dì
days in Irish: Lá
days in Scottish Gaelic: Là
days in Galician: Día
days in Korean: 날
days in Croatian: Dan
days in Iloko: Aldaw
days in Indonesian: Hari
days in Inuktitut: ᖃᐅ/qau
days in Icelandic: Sólarhringur
days in Italian: Giorno
days in Hebrew: יממה
days in Javanese: Dina
days in Kara-Kalpak: Ku'n (waqıt)
days in Georgian: დღე
days in Kazakh: Күн
days in Swahili (macrolanguage): Siku
days in Haitian: Jou
days in Kurdish: Roj (dem)
days in Ladino: Dia
days in Lao: ມື້
days in Latin: Dies
days in Latvian: Diena
days in Lithuanian: Para
days in Lingala: Mokɔlɔ
days in Lombard: Dí
days in Hungarian: Nap (időegység)
days in Macedonian: Ден
days in Malay (macrolanguage): Hari
days in Mongolian: Өдөр
days in Dutch: Dag
days in Dutch Low Saxon: Dag
days in Japanese: 日
days in Norwegian: Dag
days in Norwegian Nynorsk: Dag
days in Narom: Jouo
days in Occitan (post 1500): Jorn
days in Low German: Dag
days in Polish: Dzień
days in Portuguese: Dia
days in Romanian: Zi
days in Quechua: P'unchaw
days in Russian: День
days in Albanian: Dita
days in Sicilian: Jornu
days in Simple English: Day
days in Slovenian: Dan
days in Somali: Maalin
days in Serbian: Дан
days in Finnish: Vuorokausi
days in Swedish: Dygn
days in Tagalog: Araw (panahon)
days in Tamil: நாள்
days in Tatar: Kön
days in Thai: วัน
days in Tajik: Рӯз
days in Turkish: Gün
days in Ukrainian: Доба
days in Volapük: Del
days in Võro: Päiv (aomõõt)
days in Yiddish: טאג
days in Yoruba: Ọjọ́
days in Contenese: 一日
days in Samogitian: Dėina
days in Chinese: 日
Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1