Commensurate means matching in size, importance, or quality, appropriately proportioned to something else. When your teacher assigns homework commensurate with your grade level, she gives you work that fits your abilities: not too easy, not impossibly hard. When someone receives a salary commensurate with their experience, they're paid an amount that matches their years of work and expertise.

The word often appears when discussing fairness and balance. If you break your neighbor's window with a baseball, a punishment commensurate with the offense might be doing chores to pay for the repair. That would be fair and proportional. Making you do chores for a year wouldn't be commensurate because it's way too much for the mistake.

Scientists use this word when comparing measurements: “The increase in study time was commensurate with the improvement in test scores,” meaning they rose together in matching amounts. In everyday life, you might say someone's confidence should be commensurate with their actual skill, meaning they shouldn't be too cocky about abilities they haven't developed yet.

The opposite would be incommensurate: wildly mismatched or out of proportion, like receiving a trophy for simply showing up.