The number of distinct locations that may be referred to with the machine address Scope Notes: For most binary machines, it is equal to 2n, where n is the number of bits in the machine address.

The range of possible unique addresses allowed by an addressing scheme.

a mapping of logical addresses into physical memory or other memory mapped devices.

The set of all legal addresses in memory for a given application. The address space represents the amount of memory available to a program. Interestingly, the address space can be larger than physical [..]

An address space is a range of valid addresses in memory that are available for a program or process. That is, it is the memory that a program or process can access. The memory can be either physical [..]

The range of memory locations that a process or processor can access. Depending on context, this could refer to either physical or virtual memory.  

<operating system, computer architecture> The range of addresses which a processor or process can access, or at which a device can be accessed. The term may refer to either physical address or virtual address. The size of a processor's address space depends on the width of the processor's address bus and address registers. Each devi [..]

(computing) A range of discrete addresses, all the address locations available in a particular, named, subset of a computer's (virtual or real) memory