adverb taking the 'to' particle, taru-adjective
clear and resounding
Literary word describing a voice or musical instrument that rings out clearly and beautifully. Used with と as an adverb or in the たる adjective form.
彼の声は嚠喨と響き渡った。
His voice rang out clear and resounding.
笛の音が嚠喨たる調べを奏でた。
The sound of the flute played a clear and resounding melody.
朗々 also describes a clear, ringing voice, but is more common and less literary than 嚠喨.
The exact derivation is uncertain; the kanji are conventionally associated with clear, ringing sounds.