A year (from Old English gēar) is the orbital period of the Earth moving around the Sun. For an observer on the Earth, this corresponds to the period it takes the Sun to complete one course throughout the zodiac along the ecliptic.
In astronomy, the Julian year is a unit of time, defined as 365.25 days of 86400 SI seconds each (no leap seconds).
There is no universally accepted symbol for the year as a unit of time. The International System of Units does not propose one. A common abbreviation in international use is a (for Latin annus), in English also y or yr.
Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, hours of daylight, and consequently vegetation and fertility. In temperate and subpolar regions, generally four seasons are recognized: spring, summer, autumn and winter, astronomically marked by the Sun reaching the points of equinox and solstice, although the climatic seasons lag behind their astronomical markers. In some tropical and subtropical regions it is more common to speak of the rainy (or wet, or monsoon) season versus the dry season.
A calendar year is an approximation of the Earth's orbital period in a given calendar. A calendar year in the Gregorian calendar (as well as in the Julian calendar) has either 365 (common years) or 366 (leap years) days.
The word "year" is also used of periods loosely associated but not strictly identical with either the astronomical or the calendar year, such as the seasonal year, the fiscal year or the academic year, etc. By extension, the term year can mean the orbital period of any planet: for example, a "Martian year" is the time in which Mars completes its own orbit. The term is also applied more broadly to any long period or cycle, such as the "Great Year".
Read more about Year: Etymology, Seasonal Year, Calendar Year, Symbol
Famous quotes containing the word year:
“Every third year you shall bring out the full tithe of your produce for that year, and store it within your towns; the Levites, because they have no allotment or inheritance with you, as well as the resident aliens, the orphans, and the widows in your towns, may come and eat their fill so that the LORD your God may bless you in all the work that you undertake.”
—Bible: Hebrew, Deuteronomy 14:28,29.
“Even an attorney of moderate talent can postpone doomsday year after year, for the system of appeals that pervades American jurisprudence amounts to a legalistic wheel of fortune, a game of chance, somewhat fixed in the favor of the criminal, that the participants play interminably.”
—Truman Capote (19241984)
“In certain savage tribes in New Guinea, they put the old people up in the trees and shake them once a year in the spring; if they dont fall out they let them live another year.”
—John Dos Passos (18961970)