The Collaborative International Dictionary of English v.0.48:
Pantile \Pan"tile`\, n. [5th pan + tile.] (Arch.) A roofing tile, of peculiar form, having a transverse section resembling an elongated S laid on its side (?). [1913 Webster]WordNet (r) 3.0 (2006):
pantile n 1: a roofing tile with a S-shape; laid so that curves overlap