Castell, a castle, fortress.

Cil, (pronounced keel) a retreat, a recess.

Clawdd, a hedge, a dyke.

Clogwyn, a precipice.

Coed, a wood.

Cors, a bog, a fen.

Craig, a rock or craig.

Croes, a cross.

Cym, a valley or glen.

Dinas, a fort, a city, or a fortified place.