Revelation of Jesus Christ
From the KJV 1611 with Strong's Concordance
G2250
ἡμέρα
hemera
{hay-mer'-ah}
Feminine (with G5610 implied) of a derivative of ἧμαι [[hemai]] (to sit; akin to the base of G1476) meaning tame, that is, gentle; day, that is, (literally) the time space between dawn and dark, or the whole 24 hours (but several days were usually reckoned by the Jews as inclusive of the parts of both extremes); figuratively a period (always defined more or less clearly by the context).
NOTE: Used widely throughout the New Testament (below are the usages from Revelation only).
day
Revelation 1:10; 4:8; 6:17; 7:15; 8:12; 9:15; 12:10; 14:11; 16:14; 18:8; 20:10; 21:25.
days
Revelation 2:10, 13; 9:6; 10:7; 11:3, 6, 9, 11; 12:6.