What's the difference between a shell and a terminal? Definitions.

[Eugeny]

Shell

A CLI-interface program that you type commands into and it interprets them. Shells can provide additional features, e.g. command aliases or background job management. Most shells can run both interactively, i.e. when you type in commands, or non-interactively, i.e. when you launch it with a script path and it executes the script instead.

Examples: Bash, ZSH, cmd.exe, PowerShell.

Terminal

A GUI program that allows you to interact with the shell and/or other programs. Terminals also provide additional features such as tabs, panes, profiles and more.

Examples: Tabby, conhost.exe, PuTTY, Xshell, gnome-terminal, Terminal.app, xterm.

Terminal multiplexer

A CLI program that hosts multiple virtual terminals inside it and switches between them or displays them side-by-side.

Examples: tmux, GNU screen

SSH client

A program that allows you to access a shell running on a different computer. It can either be a CLI program (e.g. OpenSSH) that runs inside a terminal, or a GUI program with a built-in terminal (PuTTY/KiTTY).