taru-adjective, adverb taking the 'to' particle
echoing beautifully; beautiful sound
Archaic literary word describing a clear, beautiful ringing sound, especially of jewels or metals striking together, or figuratively of a melody. Used in classical Japanese texts.
古典では、玉が触れ合う音を「璆鏘」と表現することがある。
In classical literature, the sound of jewels touching each other is sometimes described as 璆鏘.
その詩には「璆鏘たる調べ」という古風な言い回しが出てくる。
In that poem, the old-fashioned phrase 璆鏘たる調べ (a beautifully echoing melody) appears.