circular
noun
line or route around an area or object
circa
noun
the movement of blood through the heart and blood vessels
circumspect
adjective
cautious; watchful
circadian
adjective
rhythmic biological cycles recurring at approximately 24-hour intervals
circumference
noun
the outer boundary of a circle
circinate
adjective
made round; ring-shaped
circumscribe
verb
to draw a line around
circumambient
adjective
surrounding; encompassing
circumnavigate
verb
to sail around