Strong’s Greek
G541 — apaugasma
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ἀπαύγασμα
apaugasma — pronounced ap-ow'-gas-mah
from a compound of 575 and 826; an off-flash, i.e. effulgence:--brightness. see GREEK for 575 see GREEK for 826
1 occurrence in the KJV.
Hebrews 1:3
Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high: