Demystifying the Jargons

• terminal is an application you execute commands from.

• directory is a synonym for a folder.

• shell is the program that actually executes your commands. Think of cmd.exe or PowerShell on Windows.
  On most linux distros, bash is usually the default shell, but I recommend using fish as your default shell and bash for writing shell scripts.
  Refer to the General Resources > Changing Shells section for a guide to list and change your shell.

• arguments are the extra options you use with a command.
  Example: grep -i bash /etc/shells
  Here, -i bash /etc/shells are arguments for grep

• path can either refer to the location of a directory or file, or a special environment variable $PATH that contains the locations from where you can launch and execute commands.

• environment variable is a shell variable that works and functions mostly like variables in any programming language.