Quick Definition
once, once for all
Strong's Definition
one (or a single) time (numerically or conclusively)
Derivation: probably from G537 (ἅπας);
KJV Usage: once
Thayer's Greek Lexicon
ἅπαξ, adverb, once, one time (from Homer down);
a. universally: 2Co_11:25; Heb_9:26; 1Pe_3:20 Rec.; ἔτι ἅπαξ, Heb_12:28 f; ἅπαξ τοῦ ἐνιαυτοῦ, Heb_9:7 (Herodotus 2, 59, etc.).
b. like Latinsemel, used of what is so done as to be of perpetual validity and never need repetition, once for all: Heb_6:4; Heb_10:2; 1Pe_3:18; Jud_1:3; Jud_1:5.
c. καί ἅπαξ καί δίς indicates a definite number (the double καί emphasizing the repetition, both once and again i. e.) twice: 1Th_2:18; Php_4:16; on the other hand, ἅπαξ καί δίς means (once and again i. e.) several times, repeatedly: Neh_13:20; 1Ma_3:30. Cf. Schott on 1Th_2:18, p. 86; (Meyer on Philippians, the passage cited).
Mounce Concise Greek Dictionary
ἅπαξ hapax 14x
once, 2Co_11:25 ; once for all, Heb_6:4 ; Heb_9:26 ; Heb_9:28 ; Heb_10:2 ; 1Pe_3:18 ; 1Pe_3:20 ; Jud_1:3 ; εἰδὼς ἅπαξ , k nowing once for ever, unfailingly, constantly, Jud_1:5 once; once for all.
Abbott-Smith Greek Lexicon
ἅπαξ ,
adv. ,
[in LXX for H259 , H6471 ;]
(a) once: 2Co_11:25 , Heb_9:26-27 ; ἔτι ἅ ., Heb_12:26-27 ; ἅ . τ . ἐνιαυτοῦ , Heb_9:7 ; καί ἅ . κ . δίς , twice: Php_4:16 , 1Th_2:18 ;
(b) once for all: Heb_6:4 ; Heb_9:28 ; Heb_10:2 , 1Pe_3:18 , Jud_1:3 ; Jud_1:5 ( MM , VGT , s.v. ).†
Moulton & Milligan — Vocabulary of the Greek NT
ἅπαξ [page 53]
P Oxy III. 471 .77 (ii/A.D.) ἅπαξ γὰρ ἐν ἔθει τῆς α [ἰσ ]χύνης γενόμενον , for when once accustomed to his shame (Edd.). In P Lond 417 .8 ( c. A.D. 346) (= II. p. 299, Selections , p. 124), we find συνχωρῆσε αὐτοῦ τοῦτω τὸ ἅβαξ (= συνχωρῆσαι αὐτῷ τοῦτο τὸ ἅπαξ ), pardon him this once a substantival use of ἅπαξ , which has been traced perhaps to Coptic influence (Deissmann LAE , pp. 206, 209) : cf. below. Note also P Giss I. 48 .10 (A.D. 202 3) οὐχ ἅπαξ παρεγράφη , not once alone, ἀλ᾽ ὁποσάκις ἕκαστα προσηνέχθη , and P Oxy VIII. 1102 .8 ( c. A.D. 146) ἐπεὶ ἅπα̣ξ π̣ροση̣̑ [λθε ] τῇ κληρονομίᾳ , having once entered on the inheritance (Ed.). Vettius Valens, p. 285 .30 has ἅπαξ τε καὶ ἀπαραιτήτως δαμάζουσιν in perpetuum (Ed.). OGIS 201 (vi/A.D.), an inscr. of King Silco of Nubia, which is very instructive for the study of foreigners Greek, has ἅπαξ in a curious idiom : thus ἓν ἅπαξ is semel , τὸ πρῶτον ἅπαξ = primum , ἅπαξ δύο = bis. Dittenberger quotes Lepsius to show that it is an effort to render a Coptic word answering to Ger. Mal , Fr. fois. In P Oxy VIII. 1138 .13 (v/vi A.D.) the words πρὸς ἅπαξ occurring at the end of a receipt are translated once for all by the editor, who compares BGU IV. 1020 .15 (vi/A.D.) : so εἰς ἅπαξ P Oxy X. 1294 .14 (ii/iii A.D.).
[Supplemental from 1930 edition]
For ἄλλα ἅπαξ = other times, see Archiv vi. p. 379.
Liddell-Scott — Intermediate Greek Lexicon
ἅπαξ [Etym: α copul. and root παγ, πήγνυμι, cf. lat. "simplex".] "once, once only, once for all", like Lat. semel, Od. , Hdt. , attic c. gen., ἅπ. τοῦ ἐνιαυτοῦ "once" in the year, Hdt. without any notion of number, after εἴπερ, ἤν, ἐπεί, ὡς, ὅταν, like Lat. ut semel, εἴπερ ἐσπείσω γ᾽ ἅπαξ if "once" you have made a treaty, Ar. ; ὡς ἅπαξ ἤρξατο "once" he had begun, Xen.
STEPBible — Tyndale Abridged Greek Lexicon
ἅπαξ
adv., [in LXX for אֶחָד, פַּעַם ;]
__(a) once: 2Co.11:25, Heb_9:26-27; ἔτι ἅ., Heb.12:26-27; ἅ. τ. ἐνιαυτοῦ, Heb.9:7; καί ἅ. κ. δίς, twice: Php.4:16, 1Th.2:18;
__(b) once for all: Heb.6:4 9:28 10:2, 1Pe.3:18, Ju 3 5 (MM, VGT, see word).†
(AS)