Georg Autenrieth, A Homeric Dictionary

δή : now, just, indeed, really, etc.; a particle marking degree of time, quality, or emphasis, mostly untranslatable by a single word; postpositive except in the initial phrases δὴ τότε, δὴ γάρ, δὴ πάμπαν, Il. 19.342; καὶ δή μοι γέρας αὐτὸς ἀφαιρήσεσθαι ἀπειλεῖς, and ‘here now,’ Il. 1.161 ; ὀκτὼ δὴ προέηκα ὀιστούς, ‘full eight already,’ Il. 8.297 (so often w. numerals); appended to adverbs of time, ὅτε δή, ὀψὲ δή, to adjectives (esp. superlatives, κάρτιστοι δή, ‘the very mightiest’), to relative and interrogative pronouns, and to other particles, ὡς δή, ironical; εἰ δή, if ‘really’; ἀλλὰ δή, (γὰρ) δή (scilicet enim); esp. in wishes or commands, μὴ δή, ‘only’; ἴθι δή, ἄγε δή, etc. δή often coalesces with a following long vowel or diphthong (‘synizesis’), δὴ αὖτε, δὴ οὕτως (not to be written δ̓).