ὀρθογώνιον
From LSJ
ἐξ ὀνύχων λέοντα τεκμαίρεσθαι → judge by the claws, judge by a slight but characteristic mark, small traits give the clue to the character of a person, deduce something from a small indication, identify a lion from its claws
English (LSJ)
τό, A rectangle, Arist.de An.413a17 ; ὀρθό-ιος, ον, rectangular, Archyt. ap. Simp. in Cat.392.8 ; τρίγωνον Ti.Locr.98a, D.L.8.12 ; κῶνος Archim.Sph. Cyl.1 Prooem.; ἐξ ὀρθογωνίου by rectangular measurement, PSI4.320.12 (i A. D.), POxy.2134.15 (ii A. D.).