A mainframe is a powerful computer designed to handle large volumes of data and support numerous users simultaneously. These systems are commonly used by large organizations for critical applications, such as transaction processing and bulk data processing. Mainframes are known for their reliability, security, and ability to run multiple operating systems at once. Mainframes often run specialized software and can connect to various devices and networks. They are essential in industries like banking, insurance, and government, where they manage vast amounts of information. The term is often associated with companies like IBM, which has been a leader in mainframe technology for decades.