taru-adjective, adverb taking the 'to' particle
Rare literary term describing dazzling brightness or brilliance, often used in classical or poetic descriptions. Functions as a taru-adjective or adverb with と.
Stars shining brilliantly.
The jewel emitted a brilliant light.
gorgeous; brilliant; dazzling; ornate
in full bloom; glorious; splendid
glaring; blazing; fiery
sore; erosion; ulceration · corruption; dissipation; degeneration
brilliant; radiant; dazzling
The kanji 爛 combines 火 (fire) and 闌 (a phonetic component suggesting 'to spread'), conveying the idea of fire spreading and producing intense light. The reading らん is the on'yomi.