1) The peg which passed through a hole at the top end of a stone slate, thereby securing it behind the laths on a roof. Formerly the pins were made of wood or bone.
1410-11 Item pro xxml sclat pynnes vjs viijd, Sibthorpe
1648 he is to make slate pins for them and he is to theack, rige and pave the whole … having mosse found, Sowerby
1705 slate pins of wood or bone, Methley
1733 slate pin wood, Wakefield
1740 600 of Slate Pins for the barn, Whitley Beaumont.