|≈||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.
Square link (sq. lk.) is an obsolete unit of UK Surveyors' Measure equal to 1089/2500 sq ft.