δυσμή, -ῆς, ἡ (= δύσις, < δύνω), [in LXX for בּוֹא, עֲרָבָה, etc. ;] mostly in pl., opp. to ἀνατολαί; __1. a setting, as of the sun (accusative to Thayer, see word, so perhaps in Luk.12:54). __2. the quarter of sunset, the west: anarth., Refs Mat.8:11 24:27, Luk.12:54 13:29, Rev.21:13.† (AS)
Thayer:
1) the setting of the sun 2) the region of the sunset, the west
δυσμή
dusmē
doos-may'
From G1416; the sun set, that is, (by implication) the western region