surname
鄺 is a rare kanji used primarily as a surname. Its standalone meaning is limited to that family-name usage.
鄺 combines 廣 (broad, wide) with the city/walled-town radical ⻏. It likely originated as a place name or clan name associated with a broad area or a settlement named 廣.
The left side 廣 suggests something broad or wide, and the right side ⻏ is a city wall. Picture a wide city wall with the family name 鄺 inscribed on it.
For コウ, imagine a broad (廣) city (⻏) named Kou, where the Kou family lives: Kou -> コウ.
—