|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
attogram or attogramme is equal to 10-18 gram (unit of mass), comes from a combination of the metric prefix atto (a) with the gram (g). Plural name is attograms.
The carat (ct) is a unit of mass equal to 200 mg (0.2 g; 0.007055 oz) and is used for measuring gemstones and pearls.