|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
The Mark (from Middle High German: Marc, march, brand) is originally a medieval weight or mass unit, which supplanted the pound weight as a precious metals and coinage weight from the 11th century.
The unified atomic mass unit or dalton (symbol: u, or Da) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass).