What Is a Terminal?
As we talked about, the terms "shell", "CLI", and "terminal" are often used to refer to the same thing: a program for issuing text-based commands.
But to get pedantic, the "terminal" is just one specific part of that program. Historically, the word "terminal" meant a physical device that you could type commands into, essentially a keyboard and a screen.
These days, when we say "terminal", we really mean "terminal emulator". A terminal emulator is a program that emulates a physical terminal. It's a program that lets you type commands into a window on your computer.
Which commands you're able to use isn't determined by the terminal emulator, but by the shell, which we'll talk about later.
Your terminal emulator is just responsible for drawing text on the screen and processing your keystrokes.