Abbott-Smith Manual Greek Lexicon
ἦχος (G2279)
4 ἦχος , -ου, ὁ (also in late and MGr., -εος, τό , Lk 21:25 ), [in LXX for חָמוֹן , etc.;] a noise , sound : Ac 2:2 ; ἦ. θαλάσσης , Lk 21:25 ; σάλπιγγος , He 12:19 . a report : seq. περί , Lk 4:37 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain