chron [time]

chronological (in order of time)

synchronize (together in time)

cide [kill]

genocide (race killer)

homicide (human killer)

cise [cut]

incision (a thin, clean cut)

precise (cut exactly right)

cord, cor [heart]

cordial (heartfelt)

coronary (relating to the heart)

corp [body]

corporation (a legal body)

corpulent (having a large body)

cosm [universe, world]

cosmos (the universe)

microcosm (a small world)

cred [believe]

incredible (unbelievable)

cycl, cyclo [wheel, circular]

bicycle (a cycle with two wheels)

cyclone (a circular wind)