These three terms are often used interchangeably, but they refer to different things. Understanding the distinction is your first step toward mastery.

A terminal (or terminal emulator) is the window application you open to type commands. On macOS, this is Terminal.app, iTerm2, Alacritty, Warp, or Kitty. It handles the display — rendering text, accepting keyboard input, and showing output. Think of it as the TV screen.

A shell is the program running inside the terminal. It's the command interpreter that reads what you type, executes commands, and returns results. Examples include zsh (the macOS default since Catalina), bash, fish, and tcsh. Think of it as the TV channel — the actual content.

The console historically referred to the physical terminal connected directly to a machine — the keyboard and screen attached to the computer itself. On modern systems, the "console" usually means the system's primary text interface (like the login screen in single-user mode on macOS, or the Linux virtual consoles accessed via Ctrl+Alt+F1-F6).

How they interact: You open a terminal emulator → it launches a shell process (usually your default shell) → you type commands into the shell → the shell interprets them and sends output back to the terminal to display.

# Check which shell you're running
echo $SHELL        # Shows your default shell (e.g., /bin/zsh)
echo $0            # Shows the current shell process

# Check your terminal emulator
echo $TERM_PROGRAM  # On macOS: "Apple_Terminal", "iTerm.app", etc.

# List available shells on your system
cat /etc/shells