'Brightness' in the Bible

who appeared in glory, and were speaking of His departure [from earthly life], which He was about to bring to fulfillment at Jerusalem.

Now Peter and those who were with him had been overcome with sleep; but when they were fully awake, they saw His glory and splendor and majesty, and the two men who were standing with Him.

if then thy whole body is lightened, not having any part darkened, the whole shall be lightened, as when the lamp by the brightness may give thee light.'