τὴν τ. ἐς χθόνα Νειλῶτιν, of the Delta, A.Pr.813; τ. ῥυθμοίId.Fr.78; βάσεισPl.Ti.55b; of the hearts of certain fish, Arist.Frr.314,330,333; of Sicily, Plb.1.42.3; of Britain, Str.4.5.1. 2.ἀριθμοὶ τρίγωνοι,
triangular
numbers, are those whose units can be disposed in a triangle, as 3 , 6 , etc., being represented by the formula
n(n
+ 1)/2, Plu.2.1003f, cf. Nicom.Ar.2.8; these numbers are also called
triangles
(τρίγωνοι), Plu. 2.744b. 3. Astrol.,
in triangular
or
trine aspect,
of planets when there are three signs of the zodiac between them, so that they are at the apices of an equilateral triangle, S.E.M.5.39, Plot.2.3.4; τ. σχηματισμοίPtol.Tetr.35, cf. Man.3.344. II. as Subst., τρίγωνον, τό,
triangle,
Ti.Locr.98a, Pl.Ti.50b, etc. 2.
a musical instrument of triangular form,
with strings of equal thickness but unequal lengths, Eup.77, Pl.Com.69.13, Pl.R.399c, Arist.Pol.1341a41, Diog.Ath.1.9; called τ. ψαλτήρια in Arist.Pr.919b12:— also as masc., πολὺς δὲ Φρὺξ τρίγωνοσS.Fr.412, cf. Ath.4.183e. 3.
one of the Athenian lawcourts,
Din.Fr.89.35, Lycurg.Fr.10, Men.1076, Paus.1.28.8, Poll.8.121. 4. the constellation
Triangulum,
Eudox. ap. Hipparch.1.2.13. 5.τρίγωνος, ἡ, name of a