Abbott-Smith Manual Greek Lexicon
ἐν-έδρα (G1747)
2 ἐν-έδρα , -ας, ἡ ( ἕδρα , a seat), [in LXX: Jos 8:7 , 9 , Ps 10:8 ( אָרַב )* ;] a lying in wait, an ambush : Ac 23:16 (Rec. ἔνεδρον , a form freq. in LXX), Ac 25:3 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain