Page in and page out are actions taken by a virtual memory manager (VMM) as it adjusts the assignments of the memory mapping hardware.
When a reference is made to a non mapped page, a page fault...
a page fault is an interrupt (or exception) to the software raised by the hardware, when a program accesses a page that is mapped in address space, but not loaded in physical memory. Wikipedia...
The initial page is referred to as the 'home page". If the page is only for language selection, or has an intro animation or graphic before entering the site its ususally referred to as a 'splash...