Annum is a Latin noun meaning year. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun It is the accusative singular of the second declension masculine noun annus (nominative), anni (genitive) [1]. The accusative case ( abbreviated ACC) of a Noun is the Grammatical case used to mark the Direct object of a Transitive In linguistics grammatical number is a Grammatical category of nouns pronouns and adjective and verb agreement that expresses count distinctions (such as "one" In Linguistics, declension (or declination) is the occurrence of Inflection in Nouns Pronouns and Adjectives indicating In Linguistics, grammatical genders, sometimes also called Noun classes are classes of nouns reflected in the behavior of associated words every noun must belong

As a unit of time, it is defined as exactly 365. 25 days (that is, the average length of a year in the Julian calendar) of 86,400 SI seconds each, representing the duration of one revolution of the Earth around the Sun. The Julian calendar, a reform of the Roman calendar, was introduced by Julius Caesar in 46 BC and came into force in 45 BC (709 Ab urbe condita Although there is no universally accepted symbol for the year, NIST SP811^[1] and ISO 31-1^[2] suggest the symbol a (in the International System of Units a is also the symbol for the are unit of area, but context is usually enough to disambiguate). Conversions One are is equivalent to Metric 00001 km2 (square kilometres 0 In English, the deprecated abbreviation yr is still frequently used.

The Unified Code for Units of Measure^[3] disambiguates the symbology by using

ar for are (unit), and:

a_t = a_t = 365. The Unified Code for Units of Measure (the UCUM) is a system of codes for unambiguously representing measurement units to both humans and machines Conversions One are is equivalent to Metric 00001 km2 (square kilometres 0 24219 days for the mean tropical year

a_j = a_j = 365. D is the fourth letter in the Latin alphabet. Its name in English is spelled dee or occasionally de (diː A tropical year (also known as a solar year) is the length of time that the Sun takes to return to the same position in the cycle of seasons as seen from Earth 25 days for the mean Julian year

a_g = a_g = 365. D is the fourth letter in the Latin alphabet. Its name in English is spelled dee or occasionally de (diː 2425 days for the mean Gregorian year

a = 1 a_j year (without further qualifier)

Contents 1 Multiples of an "annum" 2 Deprecated units 3 See also 4 References

Multiples of an "annum"

• per annum means "yearly". D is the fourth letter in the Latin alphabet. Its name in English is spelled dee or occasionally de (diː A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun

• kiloannum, usual symbol ka, is a unit of time equal to one thousand years. A millennium (pl millennia) is a period of Time equal to one thousand Years (from Latin la mille, thousand and la annum

• megaannum, usual symbol Ma, is a unit of time equal to one million (10⁶) years. For other uses see Time (disambiguation Time is a component of a measuring system used to sequence events to compare the durations of The word million In standard English, the -lli- in million is pronounced with an l-sound followed by a It is commonly used in scientific disciplines such as geology, paleontology, and celestial mechanics to signify very long time periods in the past. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Palaeontology redirects here For the Scientific journal, see Palaeontology (journal. Celestial mechanics is the branch of Astrophysics that deals with the motions of Celestial objects The field applies principles of Physics, historically For example, the dinosaur species Tyrannosaurus rex was abundant approximately 65 Ma (65 million years) ago (ago may not always be mentioned; if the quantity is specified while not explicitly discussing a duration, one can assume that "ago" is implied; "mya" includes "ago" explicitly. Tyrannosaurus ( or, meaning 'tyrant lizard' is a Genus of Theropod Dinosaur. In Astronomy, Geology, and Paleontology, mya or " mya " is an abbreviation for "million years ago". ). In astronomical applications, the year used is the Julian year of precisely 365. In Astronomy, a Julian year (symbol a) is a unit of measurement of Time defined 25 days.

• gigaannum, usual symbol Ga, is a unit of time equal to 10⁹ years (one billion on the short scale, one milliard on the long scale). Milliard is a French -derived word meaning the number 1000000000 (109 one thousand million SI prefix Giga) It is commonly used in scientific disciplines such as cosmology and geology to signify extremely long time periods in the past. Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit For example, the formation of the Earth occurred approximately 4. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 57 Ga (4. 57 billion years) ago.

• teraannum, symbol Ta, is a unit of time equal to 10¹² years (one trillion on the short scale, one billion on the long scale). It is an extremely long unit of time, about 70 times as long as the age of the universe. The age of the Universe is the time elapsed between the theory of the Big Bang and the present day The expected life span of a small red dwarf star. According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool Star, of the Main sequence, either late K

• petaannum, symbol Pa, is a unit of time equal to 10¹⁵ years (one quadrillion on the short scale, one billiard on the long scale). This list compares various sizes of positive Numbers including counts of things Dimensionless quantity and probabilities. The half-life of the nuclear isomer tantalum-180m is about 1 Pa^[4]. Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73

• exaannum, usual symbol Ea, is a unit of time equal to 10¹⁸ years (one quintillion on the short scale, one trillion on the long scale). Names of numbers larger than a quadrillion are almost never used for reasons discussed further below The half-life of tungsten-180 is 1. Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 8 Ea.

Deprecated units

• bya - Formerly used for Ga (ago)
• byr - Formerly used for Ga (either elapsed or ago)
• mya - Formerly used for Ma (ago)
• myr - Formerly used for Ma (either elapsed or ago)
• tya (sometimes spelled kya) - formerly used for ka (ago)
• kyr - Formerly used for ka (either elapsed or ago)

These are deprecated units because (except for kyr) they do not use accepted SI prefixes and because the suffixes ya and yr are not accepted SI units for time as ya could be mistaken for yoctoannum. An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol to form a Decimal multiple or

See also

• Before Present
• tya

References

Before Present (BP years are a time scale used in Archaeology, Geology, and other scientific disciplines to specify when events in the past occurred In Astronomy, Geology, and Paleontology, tya, sometimes also kya, is an Acronym for thousand years ago and is used as a

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