Definition - What does Terminal Emulation mean?
Terminal emulation is the ability to make a given computer appear like an actual terminal or client computer networked to a server or mainframe. Today, this is often done via software to access data or programs on the server or mainframe, which are usually only available to the terminal being emulated.
Techopedia explains Terminal Emulation
A terminal emulation program operates as any other application. However, if emulating an older terminal or mainframe, the interface may be text only.
Some well established companies (banks, insurance companies and governments) may have decades-old programs running on mainframe computers. The terminals are long obsolete but are now emulated by terminal emulation software, which can access applications on mainframes still in use.
Many terminal emulators have been developed for various terminals. Some examples are VT220, Data General D211, Sperry/Unisys 2000-series UTS60, ADDS ViewPoint and Wyse 50/60. Some terminal emulation software actually emulates other software emulation programs. Examples are xterm and many Linux console terminals. Other software just emulates a standard (such as ANSI) - found on many operating systems such as DOS, Unix and GUI operating systems such as Windows and MAC.