## BIG IDEAS - Length ($l$) is defined as the measure of the distance between two points. - The SI unit of length is meter (m). - Common units are centimeter (cm) and kilometer (km). - Measure length with a measuring tape, meter stick, or meter ruler. - The SI unit of measure for length is the [[Meter|meter]]. Americans continue to use inches, feet, and miles. --- ## Redefinition of Inch In 1958, a conference of English-speaking nations agreed to unify their standards of length and mass, and define them in terms of metric measures. The American yard was shortened and the imperial yard was lengthened as a result. ### Dimension Physical dimensions are the basic units of measurement that define [[Physical quantity|physical quantities]]. These are expressed using fundamental units such as length, $[L]$. ### Symbol The lowercase $l$ is commonly used for length, [[Distance|distance]], or a linear dimension. For example, $l$ can represent the length of a rod or the distance between two points. --- Return [[Home|Home]] | [[SI units]] | [[Physical constant|Physical constants]] | [[Base Units]] | [[Mass]] | [[Time]]