medium build
Describes a person's body type that is neither fat nor thin. Often used in the set phrase 中肉中背 (ちゅうにくちゅうぜい).
See also: 中肉中背 (ちゅうにくちゅうぜい)
He is of medium build and average stature.
A man of medium build was standing there.
meat of medium quality
Used in contexts like grading meat, where it refers to a middle tier of quality, not the highest grade.
This restaurant serves medium-quality steak at a reasonable price.
medium build
Compound of 中 (ちゅう, 'middle') and 肉 (にく, 'flesh'). The body-type sense is a straightforward extension of 'medium flesh'.