Leakage is when something escapes from where it's supposed to be contained, usually slowly and unintentionally. When a bicycle tire has a slow leak, air seeps out through a tiny hole. When a roof has leakage during a rainstorm, water drips through cracks into your house. Leakage can happen with liquids, gases, or even information.

The word emphasizes the gradual, unwanted nature of what's escaping. A dam might develop leakage over time as water seeps through small cracks in the concrete. A company might worry about information leakage when confidential details accidentally reach competitors or the public. Scientists studying a chemical reaction might need to prevent gas leakage from their sealed containers.

Leakage differs from a sudden spill or burst. When you knock over a glass of milk, that's not leakage, it's an immediate accident. But when your water bottle slowly drips in your backpack throughout the school day, creating a puddle by lunchtime, that's leakage. The slow, persistent nature of leakage often makes it more frustrating than dramatic accidents because it can go unnoticed until it causes real problems.