circumference (n.)

"line that bounds a circle" (loosely, "any boundary line"), late 14c., from Latin circumferentia, neuter plural of circumferens, present participle of circumferre "to lead around, take around, carry around," from circum "around" (see circum-) + ferre "to carry," from PIE root *bher- (1) "to carry," also "to bear children." A loan-translation of Greek periphereia "periphery, the line round a circular body," literally "a carrying round" (see periphery). Related: Circumferential.