Quick Definition
when, since
Strong's Definition
since now, i.e. (of time) when, or (of cause) whereas
Derivation: from G1893 (ἐπεί) and G1211 (δή);
KJV Usage: after that, because, for (that, -asmuch as), seeing, since
Thayer's Greek Lexicon
ἐπειδή, conjunction (from ἐπεί and δή), Latincumjam, when now, since now (cf. Winer's Grammar, 434 (404), 448 (417); Ellicott on Php_2:26);
1. of time; when now, after that; so once in the N. T.: Luk_7:1 L T Tr text WH text
2. of cause; since, seeing that, forasmuch as: Mat_21:46 (R G L); Luk_11:6; Act_13:46; Act_14:12; Act_15:24; 1Co_1:21-22; 1Co_14:16; 1Co_15:21; (2Co_5:4 Rec.st); Php_2:26.
Mounce Concise Greek Dictionary
ἐπειδή epeidē 10x
since, because, in as much as, Mat_21:46 ; Luk_11:6 ; Act_13:46
Abbott-Smith Greek Lexicon
ἐπει -δή ,
conj .;
1. of time, when now, after that: Luk_7:1 ( WH , txt .).
2. Of cause, seeing that, forasmuch as: Luk_11:6 , Act_13:46 ( WH , txt ., RV ) Act_14:12 ; Act_15:24 , 1Co_1:21-22 ; 1Co_14:16 ; 1Co_15:21 , Php_2:26 .†
Moulton & Milligan — Vocabulary of the Greek NT
ἐπειδή [page 230]
For the causal reference of this word, as in Php_2:26 , cf. P Tebt II. 382 .80 (B.C. 30 A.D. 1) ἐπειδ̣[ὴ ] Κάστωρ . . . παρακεχώρη (κεν ) ἀπὸ τῶν λοιπῶν τοῦ κλήρου . . . Ἀκουσιλάωι γράφ [ομεν ὑμῖν ἵν᾽ η ἐπιμε ]λ̣ὲς κτλ ., whereas Castor has ceded the remainder of his holding to Acusilaus, we write to you in order that you may be careful, etc., P Oxy VII. 1061 .2 (B.C. 22) ἐπειδὴι καὶ ἄλλοτέ σοι ἐγράψαμεν . MGr ἐπειδή (ς ), because, since.
STEPBible — Tyndale Abridged Greek Lexicon
ἐπει-δή
conj.;
__1. of time, when now, after that: Luk.7:1 (WH, txt.).
__2. Of cause, seeing that, forasmuch as: Luk.11:6, Act.13:46 (WH, txt., RV) Act.14:12 15:24, 1Co.1:21-22 14:16 15:21, Php.2:26.†
(AS)