|≈||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.
A twip (abbreviating "twentieth of a point", "twentieth of an inch point", or "twentieth of an Imperial point") is a typographical measurement, defined as 1/20 of a typographical point. One twip is 1/1440 inch or 17.639 µm.