The circumference is the distance all the way round a circle. Measure the circumference, the earth's circumference, circumference and diameter.
It equals pi times the diameter, which is the definition of pi rather than a fact about circles. Eratosthenes measured the earth's circumference around 240 BC using shadows in two Egyptian cities and got within a few per cent. Note perimeter, which is the same idea for a shape with straight sides; and that the Latin means carrying around.
1nouncircumferenceThe distance all the way round a circle.
“It took three of us, holding hands, to reach around the circumference of the old oak.”
circumference is a measured distance.
Latin circumferentia is circum, around, plus ferre, to carry. It was coined to translate the Greek periphereia, and it displaced the Old English ymbgang.
Proto-Indo-European
*(s)ker- (turn)
Latin
circumferentia
English, today
circumference
Built from
From Latin circumferentia, from circum (“around”) + ferō (“to carry”). Displaced native ymbgang.
Etymology from Wiktionary, CC BY-SA