Definition:Imperial/Length/Inch
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Definition
The inch is an imperial unit of length.
\(\displaystyle \) | \(\) | \(\displaystyle 1\) | inch | ||||||||||
\(\displaystyle \) | \(=\) | \(\displaystyle 2 \cdotp 54\) | centimetres | ||||||||||
\(\displaystyle \) | \(=\) | \(\displaystyle 0 \cdotp 0254\) | metres |
This definition is exact, and is how the imperial unit of length is defined.
Linguistic Note
The word inch derives ultimately from the same root as ounce, that is, from the Latin word uncia, meaning $\dfrac 1 {12}$ part.
In this context, the inch is of course the $\dfrac 1 {12}$ part of a foot.
From the same root, the uncial letters of a mediaeval manuscript are letters which are an inch high.
Despite the gradual migration to the metric system, the word inch still lives on as a rhetorical flourish for a small distance, for example:
- Slowly and steadily they inched forward ...
Sources
- 1944: Alfred E. Holbrow: Geometrical Drawing (12th ed.) ... (previous) ... (next): Section $\text I$. Introduction
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $12$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $12$
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): Entry: inch
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): Entry: inch