μάρτυρος
From LSJ
English (LSJ)
ὁ, Ep. form for
A μάρτυς, ἐστὲ μάρτυροι Il. 2.302, etc.; also in Central Greece, IG9(1).226 (Drymaea), 364 (Naupactus), GDI 1684, al. (Delph.), etc.: sg. once in Od., οἷσιν ἄρα Ζεὺς μάρτυρος 16.423, cf. PGen.54.6 (iv A.D.). (Zenod. rejected this form, but it is defended in Sch. Il.Oxy.1087.22.)
German (Pape)
[Seite 97] ὁ, altepisch = μάρτυς, Zeuge, οἷσιν ἄρα Ζεὺς μάρτυρος, Od. 16, 423, mit dem Nebenbegriffe des Beistandes u. Schutzes; im plur., ἐστὲ μάρτυροι, Il. 2, 302, öfter, θεοὶ γὰρ ἄριστοι μάρτυροι ἔσσονται, 22, 255; vgl. Duentzer Zenodot. p. 52; der plur. steht auch Inscr. 1702 ff.