The method [Kernel#autoload](<http://www.rubydoc.info/stdlib/core/Kernel%3Aautoload>) registers filename to be loaded (using Kernel::require) the first time that module (which may be a String or a symbol) is accessed.

autoload :MyModule, '/usr/local/lib/modules/my_module.rb'

The method Kernel#autoload? returns filename to be loaded if name is registered as autoload.

autoload? :MyModule  #=> '/usr/local/lib/modules/my_module.rb'