Quick Definition
ὄγδοος, η, ον Adj eighth
Strong's Definition
from 3638; the eighth
KJV Usage: eighth
UBS Dictionary of the Greek New Testament
adjc. | -η, -ον | ὀκτώ
60.55 · Number · First, Second, Third, Etc. [Ordinals]
eighth eighth in a series involving either time, space, or set In a number of languages one does not speak of ‘the eighth’ as being the eighth item in a set. Often it is far more usual to say ‘one together with seven others.’ This same system may apply to all ordinals in a language.
UBS Dictionary of the Greek New Testament © United Bible Societies, licensed CC BY-SA 4.0.
Mounce Concise Greek Dictionary
ὄγδοος ogdoos 5x
the eighth, Lk. 1:59; Acts 7:8; 2 Pet. 2:5; Rev. 17:11; 21:20*
Abbott-Smith Greek Lexicon
ὄγδοος, -η, -ον, the eighth: Lk 1:59, Ac 7:3(LXX), Re 17:11 21:20; one of eight, with seven others (usually, in this sense, with αὐτός added, but cf. Plat., Legg., iii, 695c; Plut., Pelop., 13; II Mac 5:27): II Pe 2:5.†
Moulton & Milligan — Vocabulary of the Greek NT
ὄγδοος, originally ὄγδοος, 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. rot (B.c. 174) ἔτους ὀγδόου, OGTS 9039 (Rosetta stone—B.C. 196) ἕως τοῦ ὀγδόου ἔτους. Cf. however P Eud 419 (before B.c. 165) ὄγδουν beside ὀγδόης, and 20. 143 ὄγδου (cited in Mayser G7. p. 294), and see also OGIS 33214 (B.c. 138-2) τὴν δὲ ὀγδόην, of the eighth day of the month.
Liddell-Scott-Jones — Greek-English Lexicon
ὄγδοος (ogdoos) — eighth. ὄγδοος, η, ον, eighth, [Refs 8th c.BC+]; ὀγδόη (i.e. ἡμέρα), ὀγδόῃ τῆς πρυτανείας [Refs 1st c.AD+] as disyllable, [Refs 8th c.BC+]