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Circumference
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<p>In <a href="/facts/Geometry/wTQf5ffQ">geometry</a>, the circumference (from Latin <i>circumferens</i>, meaning "carrying around") is the <a href="/facts/Perimeter/yQv1AajA">perimeter</a> of a <a href="/facts/Circle/9fy5ggKn">circle</a> or <a href="/facts/Ellipse/1wUDnGxY">ellipse</a>. The circumference is the <a href="/facts/Arc_length/QgTrmLxY">arc length</a> of the circle, as if it were opened up and straightened out to a <a href="/facts/Line_segment/V8E0M4qk">line segment</a>. More generally, the perimeter is the <a href="/facts/Curve_length/QgTrmLxY">curve length</a> around any closed figure. Circumference may also refer to the circle itself, that is, the <a href="/facts/Locus_(geometry)/t4swdGJq">locus</a> corresponding to the <a href="/facts/Edge_(geometry)/3lFN6sEz">edge</a> of a <a href="/facts/Disk_(geometry)/DgMVr97H">disk</a>. The circumference of a sphere is the circumference, or length, of any one of its <a href="/facts/Great_circle/x4fq6eNm">great circles</a>. </p>