This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鏧 combines 殸 (a component associated with sound or stone chimes) with 金 (metal). The exact historical development is uncertain, but it likely relates to a metal object that produces sound.
The top part 殸 suggests sound, and the bottom 金 is metal. Imagine a metal bell or gong that rings out loudly.
For ロウ, picture a low, resonant gong sound: low -> ロウ, as the metal gong echoes.