Overload means to put too much of something onto or into something else, beyond what it can safely handle. When you overload a backpack with books, it becomes so heavy the straps might break. When you overload an electrical outlet by plugging in too many devices, you risk tripping a circuit breaker or even causing a fire.

The word suggests crossing a dangerous threshold. A washing machine can handle a certain amount of laundry, but if you overload it, the machine might shake violently or fail to clean properly. A bridge has a weight limit because engineers know that overloading it with too many heavy trucks could cause it to collapse.

People can experience overload too. When your schedule gets overloaded with activities, homework, and commitments, you might feel overwhelmed and unable to do any of them well. Information overload happens when you're trying to learn or process so much at once that your brain can't keep up, like studying for five tests in the same night.

The key idea is excess: adding more than the system, person, or thing was designed to handle.

As a noun, an overload is the extra amount itself, or the state of having too much to handle.