In the past, mainframe computers and minicomputers had a physical screen and keyboard and a panel of switches and dials and lights that permitted complete overall control of the computer, usually with a human operator continuously seated in front of them. This was called the console. It was pretty cool, especially the lights and switches.
Over time, computers required less attention, and the panel disappeared due to the expense of producing it. Some computers still have a physical console, but they may also be managed remotely.
Today, a console is usually a concept, not a physical object. It’s a terminal or PC or window that provides a text display and keyboard and allows overall control of the computer. It may simply be a window in a GUI. It usually has some sort of unique capabilities. The term may also describe any interface that is just text and a keyboard.
Consoles still have their charm. Starting up a large mainframe (which isn’t done often, since they run 24 hours a day) and watching 90,000 users come online at once around the world is impressive, as was watching a dozen line printers print startup banners simultaneously. Most mainframes have a final message that they print at the end of the startup process, and if you’re a conscientious operator, seeing that message can produce goosebumps, because it means the whole world (perhaps a half million users or more) is suddenly back online and open for business.