cent-um hundred: cent, century, centurion, centenary, centi-grade.
cern-o (crēt-), I distinguish, decide; cert-us, fixed: dis-cern, dis-cri-minate, discreet, con-cern, decree, se-crete, secret-ary, certain, certi-ficate.
circ-um, around; circ-us, circle: circle, circular, circuit (ĭ-), circum-spect.
cīvi-s, citizen; cīvi-tas, state, city: civic, civilize, civilian, city and citadel.
clam-o, (clamāt-), I cry out: claim, exclaim, declamation.
claud-o, (claus-), I shut; in compounds, -clūdo (clūs-): clause, close, ex-clude.
clīv-us, slope; in-clīno (clīnāt-), bend: de-clivity, in-clination, declension.
colo, (cult-), I till, revere; colon-us, farmer: colony, cult, culture.
cōmmodus, convenient: commodity, incommode, accommodate.