physical address

A physical address is a binarynumber in the form of logical high and low states on an address busthat corresponds to a particular cell of primary storage(also called main memory), or to a particular register in a memory-mapped I/O(input/output) device.

In a computer with virtual memorythat incorporates memory management, the physical address differs from the virtual address so a memory management unit (MMU) translates the virtual address into a physical address, enabling each running process to "think" that it has all the primary storage to itself.