The staple food eaten regularly as the main part of meals; varies by culture (e.g., rice in Japan, bread or noodles in other regions).
日本の主食は一般的に米だが、最近はパンを主食にする家庭も増えている。
Rice is generally the staple food in Japan, but recently more households have been making bread their staple.
炭水化物は体にとって重要な主食の構成要素だ。
Carbohydrates are an important component of staple foods for the body.
その地域の主食はトウモロコシだ。
The staple food of that region is corn.