noun
scraped meat from the spine of a fish or beef
Culinary term for the flesh left on the spine after filleting, especially tuna; often used in sushi or as a topping.
マグロの中落ちを軍艦巻きにしました。
I made gunkan-maki with scraped tuna meat from the spine.
Compound of 中 (naka, 'inside') and 落ち (ochi, 'falling/dropping'), referring to the meat that falls or is scraped from between the bones.