- the boundary of a specific area or geometric figure, esp of a circle
- the length of a closed geometric curve, esp of a circle. The circumference of a circle is equal to the diameter multiplied by π
WordReference Random House Learner's Dictionary of American English © 2026
cir•cum•fer•ence /sɚˈkʌmfərəns/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- Mathematicsthe outer boundary, esp. of a circular area;
perimeter: We walked around the circumference of the lake. - Mathematicsthe length of such a boundary:The circumference of a circle is equal to π times the diameter.
cir•cum•fer•ence
(sər kum′fər əns),USA pronunciation n.
- Mathematicsthe outer boundary, esp. of a circular area;
perimeter:the circumference of a circle. - Mathematicsthe length of such a boundary:a one-mile circumference.
- the area within a bounding line:the vast circumference of his mind.
- Late Latin circumferentia, equivalent. to circum- circum- + fer- (stem of ferre to carry) + -entia -ence
- Middle English 1350–1400
- 1. periphery, circuit.
Collins Concise English Dictionary © HarperCollins Publishers::
circumference /səˈkʌmfərəns/ n
'circumference' also found in these entries (note: many are not synonyms or translations):
about
- ambit
- centre
- circle
- cycloid
- daisywheel
- epicycloid
- Eratosthenes
- girth
- hypocycloid
- mil
- pi
- point
- quadrant
- radian
- radius
- right angle
- round
- semicircle
- spline
- Uluru/Ayers Rock
- arc
- around
- basketball
- bilge
- cablet
- camber
- casting wheel
- center
- circ
- circuit
- circum-
- circumferential
- circumferentor
- clincher tire
- concyclic
- diameter
- epicycle
- expand
- giant puffball
- limaçon
- periphery
- radial
- trend
- waistline
- zone
- slant height
- slender