διάμετρος

διάμετρος, ον, A. diametrical: Astrol., diametrically opposed, Ptol. Tetr. 115, Man. 1.89. II. Subst. δ. (sc. γραμμή), ἡ, diagonal of a parallelogram, Pl. Men. 85b,al.; κατὰ δ. συντίθεσθαι, of triangles, by the hypotenuses, Id. Ti. 54d; diameter of a circle, Arist. Cael. 271a12, etc.; axis of a sphere, Id. MA 699a29; diameter of other curves, Apollon.Perg. Con. 1Def. 1; axis of a conic, Archim. Aequil. 2.10; ἡ κατὰ διάμετρον σύζευξις, of circles, Arist. EN 1133a6; τὰ κατὰ δ. Id. Cael. 277a24; κεῖσθαι κατὰ δ. Id. Mete. 363a34, al.; κατὰ δ. κινεῖσθαι, of quadrupeds, which move the legs cross-corner-wise, as horses when trotting (opp. κατὰ πλευρὰν κινεῖσθαι ambling, in which the legs on either side move together), Id. HA 490b4, IA 712a25, cf. Plu. 2.43a; ἐκ διαμέτρου ἀντικείμενος, of planets, in opposition, PMag. Par.1.2221; ἐκ διαμέτρου ἡμῖν οἱ βίοι Luc. Cat. 14. 2. prob. mitre-square, Ar. Ra. 801.