Circumfrence
Durand Line ,,
out of bounds
also known as the baseline, it's the out of bounds lines right behind the basketball hoops.
A boundary line.
the back boundary line, and the long service line
The Himalayan Mountains is the natural boundary between China and India. China and India have fought battles over disputed parts of this boundary.
The line that seperates one air mass from another is called a boundary.
It is called a divergent plate boundary.
Mason Dixon Line.
Tree line
Yes. It is called a state line.