γνωμον-ικός · gnōmon-ikos — LSJ
judging by rule, fit to judge of, skilled in
judging by rule, X. Mem. 4.2.10; fit to judge of, skilled in a thing, τινός Pl. R. 467c, Iamb. Myst. 3.27.
II of, concerning sun-dials, expert in sun-dials, the art of making them
(γνώμων II.2.a) of or concerning sun-dials, θεωρήματα Hipparch. 1.9.8, cf. Str. 1.1.20: -κός, ὁ, expert in sun-dials, AP 14.139, Gal. 5.652, Procl. Hyp. 5.54: ἡ -κή (sc. τέχνη), the art of making them, Vitr. 1.3. Adv. -κῶς Str. 2.1.35.
2 forming a γνώμων
forming a γνώμων (II.2.c), τρίγωνα Iamb. in Nic. p.71 P. Adv. -κῶς ib. p.77 P.