autoload

autoload is a built-in function in `C source code'.

(autoload FUNCTION FILE &optional DOCSTRING INTERACTIVE TYPE)

Define FUNCTION to autoload from FILE.
FUNCTION is a symbol; FILE is a file name string to pass to `load'.
Third arg DOCSTRING is documentation for the function.
Fourth arg INTERACTIVE if non-nil says function can be called interactively.
Fifth arg TYPE indicates the type of the object:
nil or omitted says FUNCTION is a function,
`keymap' says FUNCTION is really a keymap, and
`macro' or t says FUNCTION is really a macro.
Third through fifth args give info about the real definition.
They default to nil.
If FUNCTION is already defined other than as an autoload,
this does nothing and returns nil.