This is the 2904th most frequent Japanese word.
もも肉
Thigh meat.
Here "もも肉" is used to refer specifically to chicken thigh meat which is commonly used in cooking.
昨晩は家で鶏もも肉を焼いた。
Last night, I grilled chicken thighs at home.
In this sentence, "もも肉" is referred generically to thigh meat as an ingredient in cooking.
もも肉を使った料理はとてもジューシーで美味しい。
Dishes made with thigh meat are very juicy and delicious.
Here "もも肉" indicates the purchased product from the supermarket, specifying the type of meat.