Cognition is the mind’s work of knowing: noticing, understanding, remembering, and learning. It is not one single thought, and it is not the same as “being clever.” Psychologists use it as a wide name for how we take in the world and make sense of it. You will meet it in school and science: “animal cognition,” “social cognition.” In everyday English, people more often just say “thinking” or “learning,” but those words are a bit narrower. Though actually, cognition covers more than slow, careful thinking (that is closer to cogitation); it also includes quick noticing and understanding without sitting down to ponder. It is a formal, academic noun. You do not say “I cognition.” You talk about someone’s cognition, or human cognition.