“By Tre, Pol, and Pen,
You shall know the Cornishmen.”
Thus, Tre [a town] gives Trefry, Tregengon, Tregony, Tregothnan, Trelawy, Tremayne, Trevannion, Treveddoe, Trewithen, etc.
Pol [a head] gives Polkerris Point, Polperro, Polwheel, etc.
Pen [a top] gives Penkevil, Penrice, Penrose, Pentire, etc.