mid-15c., "revolving, rotation, act of rolling around," noun of action from past participle stem of Latin circumvolvere "to revolve through, to roll around" (see circumvolve). Meaning "one of the windings of a twisted thing" is from 1560s.
circumstances
circumstantial
circumstantiate
circumvent
circumvention
circumvolution
circumvolve
circus
cire
cirque
cirrhosis