If someone has a seizure, they have a sudden violent attack of an illness, especially one that affects their heart or brain.

If there is a seizure of power or a seizure of an area of land, a group of people suddenly take control of the place, using force.

When an organization such as the police or customs service makes a seizure of illegal goods, they find them and take them away.

If a financial institution or a government makes a seizure of someone's assets, they take their money or property from them because they have not paid money that they owe.