"Infarstructure as a Service' is a provision model in which an organization outsources the equipment used to support operation, including store, hardware , server and networking componenta. The service provider owns the equipment and is responsible for housing running and maintaining it" (from search cloud computing.com)
the two definition are similar, but the focus in laas is more is more on the nuts and bolts of the overall campus IT function through purchasing a service level, not hardware and software.