ἄρβηλος

A. semicircular knife, used by cobblers, i.e. leather-workers (ἄρβηλοι γὰρ τὰ δέρματα Hsch. s.v. ἀνάρβηλα), Nic. Th. 423.

II. Geom., figure resembling it in shape, contained by three semicircles with coincident diameters <*>, Papp. 208.12.