Cooking is the process of preparing food by heating it, which changes its taste, texture, and safety. When you cook an egg, the heat transforms it from a liquid into a solid. When you bake bread, heat turns soft dough into a crusty loaf. Cooking kills harmful bacteria that might make you sick and often makes food easier to digest.

People cook in many ways: boiling pasta in water, roasting a chicken in an oven, grilling vegetables over flames, or frying rice in a pan. Each method uses heat differently to create different results. The Maillard reaction, which happens when proteins and sugars get hot enough, creates the delicious brown crust on grilled meat or toasted bread.

Cooking is one of humanity's most important inventions, dating back hundreds of thousands of years. Learning to cook food over fire gave early humans more energy from their meals and helped their brains grow larger. Today, cooking remains a practical skill and a creative art. Some people follow recipes precisely, like following instructions in science class. Others improvise and experiment, tasting and adjusting as they go.

The word also means “happening” or “being prepared” in informal speech. If someone asks what's cooking?, they want to know what's going on or what plans are underway.