Baker's dozen
A dozen (commonly abbreviated doz or dz) is a grouping of twelve. The dozen may be one of the earliest primitive groupings, perhaps because there are approximately a dozen cycles of the moon or months in a cycle of the sun or year. Twelve is convenient because it has the most divisors of any number under 18. The use of twelve as a base number, known as the duodecimal system (also as dozenal), originated in Mesopotamia (see also sexagesimal). This could come from counting on one's fingers by counting each finger bone with one's thumb. Using this method, one hand can count to twelve, and two hands can count to 144. Twelve dozen (122 = 144) are known as a gross; and twelve gross (123 = 1,728, the duodecimal 1,000) are called a great gross, a term most often used when shipping or buying items in bulk. A great hundred, also known as a small gross, is 120 or ten dozen. A baker's dozen, also known as a big or long dozen, is 13. Varying by country, some products are packaged or sold by the dozen, often foodstuff (a dozen eggs). Dozen may also be used to express a large number of items as in "several dozen" (ex. dozens of people came to the party).
The English word dozen comes from the old form douzaine, a French word meaning "a group of twelve" ("Assemblage de choses de même nature au nombre de douze" — (translation: A group of twelve things of the same nature as defined in the eighth edition of the Dictionnaire de l'Académie française). This French word is a derivation from the cardinal number douze ("twelve", from Latin duodĕcim) and the collective suffix -aine (from Latin -ēna), a suffix also used to form other words with similar meanings such as quinzaine (a group of fifteen), vingtaine (a group of twenty), centaine (a group of one hundred), etc. These French words have synonymous cognates in Spanish: docena,quincena, veintena, centena, etc. English dozen, French douzaine, Catalan dotzena, Persian dowjin "دوجین", Arabic durzen "درزن", German Dutzend, Dutch dozijn, Italian dozzina and Spanish docena, are also used as indefinite quantifiers to mean "about twelve" or "many" (as in "a dozen times", "dozens of people").
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