Lexical Definition

‎δυσμή‎ dysmḗ (doos-may') west G:N-F
from ‎δύνω‎

west.

Abbott-Smith

δυσμή, -ῆς, ἡ (= δύσις, < δύνω), [in LXX for בּוֹא, עֲרָבָה, etc. ;]
mostly in pl., opp. to ἀνατολαί;
1. a setting, as of the sun (acc. to Thayer, s.v., so perhaps in Lk 12:54).
2. the quarter of sunset, the west: anarth., Mt 8:11 24:27, Lk 12:54 13:29, Re 21:13.†

Abbott-Smith References

Book Refs
Matthew 8:11 · 24:27
Luke 12:54 · 13:29
Revelation 21:13

Liddell-Scott-Jones

δυσμή, ,

(δύω) ={δύσις}, setting, mostly in plural, ἀελίου δ. [Refs 5th c.BC+]; ἐπὶ δυσμῇσιν ἐών at the point of setting, [Refs 5th c.BC+]

__II the quarter of sunset, west, ἀπὸ ἑσπέρης τε καὶ [ἡλίου] δυσμέων [Refs 5th c.BC+]; opposed to ἀνατολαί, [Refs 4th c.AD+]:—also δυθμή, [Refs 3rd c.BC+]