The special forms alias, use, import, and require are ways of accessing functions or macros outside of the current module. The forms alias and import are used to be able to refer to functions without having to use their fully qualified names. The form use is used to add functionality to the current module by running a macro from another module. When macros are used from an external module, require is needed to make the macros available to the compiler at compile time.
Alias
Used to shorten the references to a specific module.
Use
Adds functionality to the current module by calling another module’s __using__ macro.
Import
Imports specific functions into the current module so they can be called without using their module name.
Require
Makes a macro from an external module available to the compiler at compile time.