Abbott-Smith Manual Greek Lexicon
ἀρραβών (G728)
3 ἀρραβών (T, ἀραβ- : II Co 1:22 5:5 ), -ώνος, ὁ , [in LXX: Ge 38:17 , 18 , 20 ( עֵרָבוֹן )*;] an earnest , part payment in advance for security, a first instalment: II Co 1:22 5:5 , Eph 1:14 . (The word is found in cl. and was prob. brought to Greece by the Phœnicians (AR, Eph. , 1:14 ). It is found in π. with both spellings (v. Milligan, NTD , 73). In MGr. ἀρραβῶνα is an engagement ring ; v. MM, s.v.)†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain