Quick Definition
eighth
Strong's Definition
the eighth
Derivation: from G3638 (ὀκτώ);
KJV Usage: eighth
Thayer's Greek Lexicon
ὄγδοος, ὀγδη, ὀγδον (from Homer down), the eighth: Luk_1:59; Act_7:8; Rev_17:11; Rev_21:20; our who has seven other companions, who with others is the eighth, 2Pe_2:5; so δέκατος, with nine others, 2Ma_5:27; cf. Matthiae, § 469, 9; Viger. edition, Herm., p. 72f and 720f; Winers Grammar, § 37, 2; (Buttmann, 30 (26)).
Mounce Concise Greek Dictionary
ὄγδοος ogdoos 5x
the eighth, Luk_1:59 ; Act_7:8 ; 2Pe_2:5 ; Rev_17:11 ; Rev_21:20
Abbott-Smith Greek Lexicon
ὄγδοος , -η , -ον ,
the eighth. Luk_1:59 , Act_7:3 ( LXX ), Rev_17:11 ; Rev_21:20 ; one of eight, with seven others (usually, in this sense, with αὐτός added, but cf. Plat ., Legg ., iii, 695 c ; Plut ., Pelop ., 13; 2Ma_5:27 ): 2Pe_2:5 .†
Moulton & Milligan — Vocabulary of the Greek NT
ὄγδοος [page 437]
ὄγδοος , originally ὄγδο ϝος , does not contract in any of its NT occurrences, and this is the general rule in the papyri and inscriptions, e.g. P Grenf I. 10 .1 (B.C. 174) ἔτους ὀγδόου , OGIS 90 .29 (Rosetta stone B.C. 196) ἕως τοῦ ὀγδόου ἔτους . Cf. however P Eud 4 .19 (before B.C. 165) ὄγδουν beside ὀγδόης , and ib. 14 .3 ὄγδου (cited in Mayser Gr. p. 294), and see also OGIS 332 .14 (B.C. 138 2) τὴν δὲ ὀγδόην , of the eighth day of the month.
Liddell-Scott — Intermediate Greek Lexicon
ὄγδοος ὄγδοος, η, ον [Etym: ὀκτω] "eighth", Lat. octavus, Hom. , etc.
STEPBible — Tyndale Abridged Greek Lexicon
ὄγδοος, -η, -ον
the eighth. Luk.1:59, Act.7:3" (LXX), Rev.17:11 21:20; one of eight, with seven others (usually, in this sense, with αὐτός added, but cf. Plat., Legg., iii, 695 with; Plut., Pelop., 13; 2Ma.5:27): 2Pe.2:5.†
(AS)