taru-adjective, adverb taking the 'to' particle
bright; shining; clear; evident
Obsolete term. Used in classical Japanese as a taru-adjective or adverb with と, meaning bright, shining, clear, or evident. Not used in modern Japanese.
古典では「炳として」のように用いられ、明らかなさまを表した。
In classical texts, it was used as 炳として, expressing a state of being bright or clear.