A lockup is a place where people are held in custody, usually temporarily. When police arrest someone, they might take them to the lockup at the police station, a secure area with cells where people wait until they go before a judge or post bail. It's similar to a jail, but it usually refers to a shorter-term holding facility.

The word paints a clear picture: someone is literally locked up, secured behind bars or locked doors so they cannot leave. You might hear someone say a suspect spent the night in the lockup before a court hearing.

In business, lockup has a completely different meaning. It refers to a period when investors or company insiders aren't allowed to sell their shares of stock. When a company first starts selling stock to the public, early investors usually face a lockup period, often several months long, where they must hold onto their shares. This prevents them from immediately selling everything and potentially causing the stock price to crash. Once the lockup period ends, those restrictions lift.