- circle law
- circle left
- circle-like
- circle-line intersection
- circle line picking
- circle map
- circle mapping
- circle method
- circle negative pedal curve
- circle net
- circle notation
- circle of altitude
- circle of antisimilitude
- circle of confusion
- circle of contact
- circle of convergence
- circle of curvature
- circle of declination
- circle of equal altitudes
- circle of friends
- circle of geodesic curvature
- circle of inversion
- circle of least confusion
- circle of longitude
- circle of meromorphy