Why are things like Gnome Terminal called "Terminal Emulators" instead of just "Terminals"?

"A terminal is the end of a line. So,
back in the day when the computer was
a mainframe serving many user
accounts, what you'd be sitting at
with your keyboard and display would
be a terminal.

A terminal emulator is when you're
using a computer (a Turing machine) to
provide the function of a terminal in
software. This usage would typically
come up because the computer would be
'imitating' a particular type of
terminal in order to communicate with
the mainframe.

A very popular terminal is/was the
VT100. So if I telnet right now to the
server of the local Freenet (if they
still exist) I'd be using VT100
emulation.

Source and more explanations are in Terminal or terminal emulator?."

"Mainly for historical reasons. In the mid 1980s, when terminal emulators were invented, they were called ""terminal emulators"" to distinguish them from the ""real thing."" The term is ambiguous nowadays, because the ""real thing"" is obsolete and only found in very old installations or museums. See terminal emulator and computer terminal.

This is a picture of a DEC (Digital Equipment Corp.) VT100, perhaps one of the most popular terminals of all time:

(Credit: Flickr user Jason Scott)"