adjective / noun
circular
SER-kyuh-ler/ˈsɜːrkjələr/
Going around in a complete loop.
The plate's circular rim forms a complete loop around its center.

Etymology
The underlying image is a small ring. Circular describes either something with that ring-like shape or movement following a circle, connecting a fixed outline with a path of motion.
In context
multiplying by the radius of the circular path so once again if the ball was moving around the path at one Radian a second
More examples
- She cuts a circular piece of fabric.
- The office sends a circular to every branch.
- Their circular argument keeps returning to the assumption it should prove.
Forms
circular · circulars
Similar words
- round
- Round describes shape broadly; circular more specifically invokes a circle or a returning loop.