Bible Dictionaries
Once

Vine's Expository Dictionary of NT Words

1: ἅπαξ

(Strong's #530 — Adverb — hapax — hap'-ax )

denotes (a) "once, one time," 2 Corinthians 11:25; Hebrews 9:7,26,27; 12:26,27; in the phrase "once and again," lit., "once and twice," Philippians 4:16; 1 Thessalonians 2:18; (b) "once for all," of what is of perpetual validity, not requiring repetition, Hebrews 6:4; 9:28; 10:2; 1 Peter 3:18; Jude 1:3 , RV, "once for all" (AV, "once"); Jude 1:5 (ditto); in some mss. 1 Peter 3:20 (so the AV).

2: ἐφάπαξ

(Strong's #2178 — Adverb — ephapax — ef-ap'-ax )

a strengthened form of No. 1 (epi, "upon"), signifies (a) "once for all," Romans 6:10; Hebrews 7:27 , RV (AV, "once"); Hebrews 9:12 (ditto); 10:10; (b) "at once," 1 Corinthians 15:6 .

3: ποτέ

(Strong's #4218 — particle — pote — pot-eh' )

denotes "once upon a time, formerly, sometime," e.g., Romans 7:9; Galatians 1:23,1 st part, RV, "once" (AV, "in times past"); 2nd part, AV and RV, "once;" Galatians 2:6 , RV marg., "what they once were" (to be preferred to the text, "whatsoever they were"), the reference probably being to the association of the twelve Apostles with the Lord during His ministry on earth; upon this their partisans based their claim for the exclusive authority of these Apostles, which Paul vigorously repudiated; in Ephesians 5:8 , RV, "once" (AV, "sometimes"). See AFORETIME , LAST , LENGTH (at), TIME (past).

Note: In Luke 23:18 , AV, pamplethei, denoting "with the whole multitude" (pas, "all," plethos, "a multitude"), is rendered "all at once," RV, "all together").

Bibliography Information
Vines, W. E., M. A. Entry for 'Once'. Vine's Expository Dictionary of NT Words. https://www.studylight.org/​dictionaries/​eng/​ved/​o/once.html. 1940.