Engawa

…In Western cuisine, it is fried or served in gratin. The meat at the base of the dorsal and anal fins is called “engawa” and is highly prized by many people. In the past, in Japan, there was no distinction between this fish and karei, and the character for “himokugyo” (flatfish) that is now read as “hirame” was also read as karei. …

*Some of the terminology that mentions "engawa" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…洋風ではフライ，グラタンなどにする。また，背びれやしりびれの付根にある肉は〈えんがわ〉と呼んで，とくに珍重する人が多い。日本では古くはカレイとの区別がされず，いまはヒラメと読ませる比目魚の字もカレイと読んでいた。…

※「えんがわ」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報