Caer, a city, a fort, a defensive wall.

Capel, a chapel.

Carn, a heap.

Carnedd, a heap of stones.

Careg, a stone.

Castell, a castle, fortress.

Cefn, ridge, the upper side, the back.

Cell, a cell; also a grove.

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

Clawdd, a hedge, a dyke.