δύο
δύο
δύω
δυοῖν
δυῶν
δυοῖσι
δυσί
can be indecl., like ἄμφω, by Hom., τῶν δύο μοιράων, δύω κανόνεσσι Il.; so in Hdt. and Attic Prose; but declined in Trag.
two, Il., etc.;—in Poets δύο or δύω may be joined with pl. Nouns, δύο δʼ ἄνδρες Il.:— εἰς δύο two and two, Xen.; σὺν δύο two together, Il., Hdt.