|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
An attometer is a unit of length, a combination of the metric prefix atto (symbol a) and the SI unit of length meter (symbol m), equal to 10−18 meter or 1.0E-18 meter and its symbol is am. Plural name is attometers.
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.