|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
A circular thou is a unit of area, equal to the area of a circle with a diameter of one thou.
A rood /ˈruːd/ is an historic English and international inch-pound measure of area, as well as an archaic English measure of length.