1.
lean meat; red meat
Meat with little fat, showing a red color. Used for both beef and other meats to distinguish lean cuts from fatty ones.
2.
red-fleshed fish (such as tuna or bonito)
Fish with red-colored flesh, as opposed to white-fleshed fish. In sushi terminology, refers specifically to the lean part of tuna.
A compound of 赤 (red) and 身 (flesh/meat), referring to meat or fish flesh that is red in color and lean.
Common collocations
Sushi terminology
At sushi restaurants, 赤身 refers to the leanest part of tuna, as opposed to 中トロ (medium fatty tuna) and 大トロ (fatty tuna belly). 赤身 is the most affordable of the three and has a clean, straightforward flavor.