A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, workstations, and personal computers.
In simple terms, mainframe computers are super-fast and reliable machines that help process large amounts of data quickly and efficiently. They are designed to ensure that critical systems, like banking and finance, remain available 24/7 without any interruptions.
Mainframe is the powerful central computer (CPU) in a data processing center, linked to thousands of users through less powerful devicessuch as PC workstations or terminals (just monitor and keyboard). Usually you don't find a mainframe in any household or small companies.