τρῐᾱκοστός,
Ionic dialect τρῐηκ-, ή, όν, thirtieth, [[ 5th c.BC: Pindarus Lyricus “O.” 8.66, “IG” 12.304.29, 5th c.BC: Herodotus Historicus 4.44, 5.89, 5th c.BC: Hippocrates Medicus “ἀφορισμοί” 4.36, 5th-6th c.BC: Xenophon Historicus “Institutio Cyri (Cyropaedia)” 5.3.6, “PCair.Zen.” 236.6 (3rd c.BC), etc.] Refs 5th c.BC+]; Aeolic dialect τρῐάκοιστος [ᾱ] [[ “IG” 11(4).1064b23 (from Delos). ] Refs]
__II ἡ τ. duty of one-thirtieth, [[ 4th c.BC: Demosthenes Orator 20.32. ] Refs 4th c.BC+]