county in Zhejiang province
鄞 is a proper noun referring to a historical county in Zhejiang province. Its standalone meaning is limited to this geographic name.
鄞 is a historical place name. The left component 堇 likely contributes the sound, while the right component ⻏ (阝) is a common element in place names, often representing a settlement or city wall.
The right side ⻏ (阝) often appears in characters for places. The left side 堇 gives the sound. Together, 鄞 is the name of a specific place in Zhejiang.
For ギン, imagine a silver (銀, ぎん) county in Zhejiang: 銀 -> ギン, and the place name 鄞 shares the same reading.