Circumference

The ratio of the circumference of a circle to its diameter was represented by the Greek letter pi. (TV: The Five Doctors)

In 2007, a whiteboard in a classroom at Deffry Vale High School referenced the circumference of a circle. (TV: School Reunion)

Martian cruisers such as the Saavid sported three nacelles which protruded from the vessel at precisely 120 degrees around its circumference. (PROSE: The Jeopardy of Solar Proximity)