Cogitation means deep, careful thinking. When you're working on a challenging math problem and sit quietly for several minutes, turning it over in your mind, considering different approaches, that concentrated mental effort is cogitation. The word suggests more than casual thought: it means really chewing on an idea, examining it from different angles.

You might see cogitation happening when a chess player stares at the board for a long time before moving, or when a scientist puzzles through a complex question. Writers engage in cogitation as they work out how to express an idea clearly. A student might spend time in cogitation before answering a difficult question on a test.

It often appears in slightly formal or literary contexts. The related verb is cogitate, meaning to think deeply: “She cogitated for hours before reaching her decision.”

Cogitation differs from daydreaming or letting your mind wander. It's focused, intentional thinking directed at understanding something or solving a problem.