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Symbol | Definition |
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≡ | exactly equal |
≈ | approximately equal to |
= | equal to |
digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |
The picometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer (American spelling) is a unit of length in the metric system, equal to 1×10−12 m, or one trillionth ( 1 / 1000000000000 ) of a metre, which is the SI base unit of length.
The French scale or French gauge system is commonly used to measure the size of a catheter. It is most often abbreviated as Fr, but can often be seen abbreviated as Fg, Ga, FR or F. It may also be abbreviated as CH or Ch (for Charrière, its inventor).