Answer 1

In the old days of Mainframe computers programmers (and users) accessed the Mainframes through terminals. These were just dumb (text only!) screen monitor and keyboard stations that were connected to the Mainframe computers.
Terminal emulators are programs that run on PCs that "emulate" those old terminals, and allow modern computers to network to Mainframes. This allows programmers and users to interact with Mainframes "the old way" via the terminal emulator, while enjoying all the other benefits of having a modern PC.
In fact, the terminal emulator, such as the IBM 3270 (https://en.wikipedia.org/wiki/3270_emulator) is just another (Console style) app on the Windows desktop for the user.
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