διπλόη

A. fold, doubling, Gal. 2.710: but usu.,

II. porous substance between the double plates in the bones in the skull, Hp. VC 1, 17, Heliod. ap. Orib. 46.9.4, Ruf. Onom. 135: generally, spongy core of bone, Paul.Aeg. 6.77; also, tissue between layers of intestine, Aret. SD 2.9: hence,

2. weak spot, flaw in metal, Pl. Sph. 267e, Ph. Bel. 71.28, Plu. 2.802b: metaph., αἱ δ. τῆς ψυχῆς ib. 715f, cf. 441d; 'patchiness', Plot. 5.2.1; also, concealed sense, in oracles, Plu. 2.407c.

III. hollow sting of the scorpion, Ael. NA 9.4.