Mainframe (noun)

A large, expensive computer designed for use by government agencies, businesses, and research institutions, often used to run centralized data processing applications and handle large amounts of data.

Origin:

From the idea of being the 'main frame' of a computer system.

Examples:

1. The bank relied on a mainframe to process all of its financial transactions.
2. The company's mainframe was outdated and in need of replacement.
3. The new mainframe was capable of processing more data than the previous model.
4. Many large corporations still use mainframes for their most critical applications.
5. The mainframe was the heart of the computer system, controlling all the other machines.