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12 (twelve ) is the natural number following 11 and preceding 13. The product of the first three factorials, twelve is a superior highly composite number, evenly divisible by 2, 3, 4, and 6. It is central to many systems of counting, including the Western calendar and units of time, and frequently appears in the Abrahamic religions. ==Name== The word "twelve" is the largest number with a single-syllable name in English. Early Germanic numbers have been theorized to have been non-decimal: evidence includes the unusual phrasing of eleven and twelve, the former use of "hundred" to refer to groups of 120, and the presence of glosses such as "tentywise" or "ten-count" in medieval texts showing that writers could not presume their readers would normally understand them that way. Such uses gradually disappeared with the introduction of Arabic numerals during the 12th-century Renaissance. It derives from the Old English ' and ', first attested in the 10th-century Lindisfarne Gospels' Book of John.〔 It has cognates in every Germanic language, whose Proto-Germanic ancestor has been reconstructed as *', from *' ("two") and suffix *' or *' of uncertain meaning.〔 It is sometimes compared with the Lithuanian ', although ' is used as the suffix for all numbers from 11 to 19 (analogous to "-teen").〔 Every other Indo-European language instead uses a form of "two"+"ten", such as the Latin ''ラテン語:duōdecim''.〔 The usual ordinal form is "twelfth" but "dozenth" or "duodecimal" (from the Latin word) is also used in some contexts, particularly base-12 numeration. Similarly, a group of twelve things is usually a "dozen" but may also be referred to as a "duodecad". The adjective referring to a group of twelve is "duodecuple". As with eleven,〔''Oxford English Dictionary'', 1st ed. "eleven, ''adj.'' and ''n.''" Oxford University Press (Oxford), 1891.〕 the earliest forms of twelve are often considered to be connected with Proto-Germanic *' or *' ("to leave"), with the implicit meaning that "two is left" after having already counted to ten.〔''Oxford English Dictionary'', 1st ed. "twelve, ''adj.'' and ''n.''" Oxford University Press (Oxford), 1916.〕 The Lithuanian suffix is also considered to share a similar development.〔 The suffix *' has also been connected with reconstructions of the Proto-Germanic for ten.〔.〕〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「12 (number)」の詳細全文を読む スポンサード リンク
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