A terminal is a text input/output environment. Historically, it was a physical device (keyboard + display). Today, it refers to software emulators (e.g., GNOME Terminal, Windows Terminal) that let users interact with a shell.
A shell is a command-line interpreter. It takes user input, parses it, and executes commands. Examples: bash, zsh, fish, sh.
TTY was originally a hardware, now a virtual device in Unix-like systems representing a terminal session. Each tty (e.g., /dev/tty1, /dev/pts/0) maps to a physical or virtual text interface.
Console is a main physical or virtual terminal directly connected to the system. On Linux, /dev/console refers to the system console, often used for kernel messages and emergency access.