Lexical Definition

‎τετράγωνος‎ tetrágōnos (tet-rag'-o-nos) square ^G:A
from ‎τέσσαρες‎ and ‎γωνία‎

foursquare.

• four-cornered, i.e. square

Abbott-Smith

τετράγωνος, -ον (< τετρα-, v. supr., + γωνία), [in LXX for רָבוּעַ and cogn. forms ;]
square: Re 21:16 (Hdt., Plat., al.).†

Abbott-Smith References

Liddell-Scott-Jones

τετράγωνος-ος [ᾰ], ον,

with four angles, but usually square, [Refs 5th c.BC+]; δοκοὶ τ. squared, [Refs 5th c.BC+]; ξύλα τ. [Refs 4th c.BC+]; τ. ἐργασία, of the Hermes-statues, [Refs 5th c.BC+]; κύκλος τετράγωνοςος ταῖς ἐπιφανείαις a ring with four surfaces, the breadth of the outer and inner equal to the depth of the two sides, [Refs 1st c.BC+]

__2 τὸ τ. a square, [Refs 5th c.BC+], and frequently in Geometry texts, but sometimes of any quadrilateral, [Refs 4th c.BC+] “*Deff.” 100, [Refs 5th c.AD+]
__2.b in Tactics, a body of men drawn up in square, [Refs 5th c.BC+]
__3 τ. ἀριθμός a square number, i.e. a number made up of two equal factors, [Refs 5th c.BC+]
__4 in quartile aspect, [Refs 1st c.BC+]
__II metaphorically, square, i.e. perfect as a square, χερσί τε καὶ ποσὶ καὶ νόῳ τετράγωνοςος τετυγμένος [τετράγωνοςον 4th c.BC: Aristoteles Philosophus “Rhetorica” 1411b27, compare “EN” 1100b21. ">Refs 4th c.BC+]
__III ἱμάτιον τ., of the χλαῖνα which hung square, while the χλαμύς took a circular form, [Refs]; contrasted with the ἡμικύκλιον formed by the Roman toga, [Refs 2nd c.BC+]
__III.2 οἱ ἔμποροι καὶ οἱ τὴν τ. ἐργαζόμενοι perhaps those who trade in the ἀγορὰ τετράγωνοςος, Durrbach Choix d'Inscrr. de Délos [Refs]
__IV adverb -νως[Refs 2nd c.AD+]