Meaning – The term register, refers to a part of internal storage having a specified storage capacity and usually intended for a specific purpose.

Some registers are used internally and cannot be accessed outside the processor, while others are user-accessible. Most modern CPU architectures include both types of registers.

Internal registers include the instruction register (IR), memory buffer register (MBR), memory data register (MDR), and memory address register (MAR).

User-accessible registers are larger than internal registers and typically hold data for a longer time. An address register contains memory addresses, which reference different blocks of memory within the system RAM.

Example of usage“Registers vary in both number and size, depending on the CPU architecture. Some processors have 8 registers while others have 16, 32, or more. For many years, registers were 32-bit, but now many are 64-bit in size. A 64-bit register is necessary for a 64-bit processor since it enables the CPU to access 64-bit memory addresses.”