"Permitted License Uses and Restrictions. This License allows you to install and use one copy of the Apple Software on a single computer at a time. This License does not allow the Apple Software to exist on more than one computer at a time, and you may not make the Apple Software available over a network where it could be used by multiple computers at the same time. "
There is a family pack which allows you to install in up to 5 machines in the same household.