Inch 14775 224817360 2008-07-10T15:30:25Z 82.73.59.206 /* Use of the inch */ - Corrected format of list : ''Inches'' redirects here. To see the ''[[Les Savy Fav]]'' album, see ''[[Inches (album)|Inches]]. For the measure of [[Precipitation (meteorology)|Precipitation]] in inches, see [[rain gauge]].'' {{unit of length| |name= inch |m= 0.0254 |accuracy=3 <!--Number of sig figs--> }} An '''inch''' (plural: '''inches'''; symbol or abbreviation: '''in''' or, sometimes, &Prime; – a [[Prime (symbol)|double prime]]) is the name of a [[Units of measurement|unit]] of [[length]] in a number of different systems, including [[English unit]]s, [[Imperial unit]]s, and [[United States customary units]]. Its size can vary from system to system. There are 36 inches in a [[yard]] and 12 inches in a [[Foot (unit of length)|foot]]. A corresponding unit of [[area]] is the [[square inch]] and a corresponding unit of [[volume]] is the [[cubic inch]]. The inch is the virtually universal unit of measurement in the [[United States]], and is very commonly used in [[Canada]] and the [[United Kingdom]]. In the US, Canada and the UK, [[Human height|personal heights]] are expressed in feet and inches by people of all ages. In Canada, personal heights are shown in metric units on most official documents such as a person's [[driver's license]] in Ontario and Québec. However, there are exceptions like Saskatchewan, which lists height on its drivers' licenses in feet and inches.<ref>[http://www.sgi.sk.ca/sgi_pub/drivers_licences/photo_id.htm Driver’s Licences: Photo ID]</ref> <!--see talk--> [[Image:Inch tape.jpg|right|250px|thumb|[[Measuring tape]] capable of measuring down to {{frac|1|32nd}} of an inch.]] == International inch == In [[1958]] the [[United States]] and countries of the [[Commonwealth of Nations]] defined the length of the international [[yard]] to be 0.9144 [[metre]]s. Consequently, the international inch is defined to be equal to 25.4 [[millimetre]]s. The international standard symbol for inch is '''in''' (see [[ISO 31-1]], Annex A). In some cases, the inch is denoted by a [[Prime (symbol)|double prime]], which is often approximated by [[quotation mark|double quotes]], and the [[Foot (unit of length)|foot]] by a [[Prime (symbol)|prime]], which is often approximated by an [[apostrophe (mark)|apostrophe]]. The two parts are then separated by a dash. For example, 6 feet 2 inches is denoted by 6′-2″. == Equivalence to other units of length == [[Image:Inch converter.jpg|right|250px|thumb|Mid-19th century tool for converting between different standards of the inch]] 1 international inch is equal to: * 1,000 [[thou (unit of length)|thou]] (1 thou is 0.001 inches.) * about 0.08333 [[Foot (unit of length)|feet]] (1 foot is equal to 12 inches.) * about 0.02778 [[yard]]s (1 yard is equal to 36 inches.) * 2.54 [[centimetre]]s (1 centimetre is equal to about 0.3937 international inches.) == Use of the inch == Even in countries where the [[metric system]] is commonplace, the inch is still sometimes used to refer to * the size category of [[computer displays]], image sensors, and [[television]] screens, * threads and diameters of [[Pipe (material)|pipes]] (see [[ISO 228]] and [[Nominal Pipe Size]]), * [[bicycle]] and [[automobile]] tires and rims (see [[ISO 5775]] and [[Tire code]]), * [[gramophone record]]s, * width of computer [[floppy diskette]]s, * diameter of [[cigar]]s, * [[pizza]] size and * clothing dimensions. == Historical origin == The origin of the inch is disputed. Historically, in different parts of the world (even different cities within the same country) and at different points in time, the inch has referred to similar but different standard lengths. The English word ''inch'' comes from Latin ''[[uncia]]'' meaning "one twelfth part" (in this case, one twelfth of a foot); the word ''[[ounce]]'' (one twelfth of a troy pound) has the same origin. In some other languages, the word for "inch" is similar to or the same as the word for "thumb"; for example, [[French language|French]]: ''pouce'' inch, ''pouce'' thumb; [[Italian language|Italian]]: ''pollice'' inch, ''pollice'' thumb; [[Spanish language|Spanish]]: ''pulgada'' inch, ''pulgar'' thumb; [[Portuguese language|Portuguese]]: ''polegada'' inch, ''polegar'' thumb; [[Swedish language|Swedish]]: ''tum'' inch, ''tumme'' thumb; [[Dutch language|Dutch]]: ''duim'' inch, ''duim'' thumb; [[Sanskrit language|Sanskrit]]: ''Angulam'' inch, ''Anguli'' Finger. Given the etymology of the word "inch", it would seem that the inch is a unit derived from the [[Foot (unit of length)|foot]], but this was probably only so in Latin and in Roman times. In English, there are records of fairly precise definitions for the size of an inch (whereas the definitions for the size of a foot are probably anecdotal), so it seems that the foot was then defined as 12 times this length. For example, the old English ''ynche'' was defined (by King David I of Scotland in about 1150) as the width of an average man's thumb at the base of the nail, even including the requirement to calculate the average of a small, a medium, and a large man's measures. To account for the much larger length later called an inch, there are also attempts to link it to the distance between the tip of the thumb and the first joint of the thumb, but this may be speculation. There are records of the unit being used circa [[Anno domini|AD]]&nbsp;1000 (both ''[[Laws of Æthelbert]]'' and ''[[Laws of Ælfred]]''). An Anglo-Saxon unit of length was the [[English units|barleycorn]]. After 1066, 3 barleycorn was equal to 1 inch; it is not clear which unit was the base unit and which the derived unit. One source says that the inch was at one time defined in terms of the [[yard]], itself supposedly defined as the distance between [[Henry I of England]]'s nose and his thumb. This is unlikely as Henry was born in 1068. Prior to the adoption of the international inch (see above), the [[United Kingdom]] and other countries of the [[Commonwealth of Nations]] defined the inch in terms of the [[Imperial unit#Measures of length|Imperial Standard Yard]]. The [[United States]] and [[Canada]] each had their own, different, definition of the inch, defined in terms of [[metric system|metric units]]. The Canadian inch was defined to be equal to 25.4 [[millimetre]]s. == Metric or decimal inch == A [[metric inch]] is the equivalent of an inch under a proposal for the metrification and unification of the [[English system]] of measures. It is now considered to be a [[List of strange units of measurement|strange unit of measurement]]. In [[Sweden]], between 1855 to 1863, the existing Swedish "working inch" (24.74 mm) was replaced by a "decimal inch" (29.69 mm) which was one tenth of the Swedish foot. Proponents argued that a decimal system simplifies calculations. However, having two different Swedish inch measures (and an English inch on top of that) proved to be complicated. Between 1878 to 1889 it was agreed to introduce the metric units. However, the decimal inch survived in some building construction trades, and decimal fractions (tenths, hundredths, thousandths) of the foot are still used in [[land surveying]]. == References == <references/> == See also == *[[English unit]] *[[Imperial unit]] *[[United States customary units]] *[[Gry (disambiguation)|Gry]] *[[Pyramid inch]] *[[Guz]] [[Category:Customary units in the United States]] [[Category:Human-based units of measure]] [[Category:Imperial units]] [[Category:Units of length]] [[ar:إنش]] [[bg:Инч]] [[ca:Polzada]] [[cv:Дюйм]] [[da:Tomme]] [[de:Zoll (Einheit)]] [[et:Toll (pikkusühik)]] [[es:Pulgada]] [[eo:Colo]] [[fa:اینچ]] [[fr:Pouce (unité)]] [[id:Inci]] [[it:Pollice (unità di misura)]] [[he:אינץ']] [[la:Uncia]] [[hu:Hüvelyk (mértékegység)]] [[mk:Инч]] [[ms:Inci]] [[nl:Duim (lengtemaat)]] [[ja:インチ]] [[no:Tomme (mål)]] [[pl:Cal]] [[pt:Polegada]] [[ro:Ţol]] [[ru:Дюйм]] [[sq:Inçi]] [[simple:Inch]] [[sl:Palec]] [[sr:Инч]] [[fi:Tuuma]] [[sv:Tum]] [[tr:İnç]] [[uk:Дюйм]] [[zh:英寸]]