Why is the secondary memory called the external memory?

Secondary memory is often referred to as external memory because it is not directly accessible by the CPU and is typically located outside the primary storage (RAM). This type of memory includes devices like hard drives, solid-state drives, and USB drives, which store data persistently even when the power is off. Unlike primary memory, which is fast and temporary, secondary memory offers larger storage capacity and retains data long-term. Thus, it serves as an external repository for data and applications that the CPU can access as needed.