To precook food is to cook it partly or fully before it is sold or stored, so that later you only need to heat it, or finish it quickly. Factories precook chicken pieces; a busy cook may precook the rice in the morning. The verb is less common on labels than the adjective precooked. Though actually, “partly” and “fully” are both allowed — the point is that the cooking happened earlier, not how far it went. It does not mean “cook badly,” and it does not mean “cook too long and ruin it.” You will meet this around ready meals, airline food, and restaurant prep.

預煮、預先烹調