What does the term "expansion slots" refer to?

The term "expansion slots" refers to slots on a motherboard that allow additional cards, also known as expansion cards, to be installed. These cards can enhance the capabilities of a computer by adding functionalities like graphics processing (through a graphics card), enhanced audio (sound card), additional network interfaces (network adapter), or other features that the original motherboard may not support. By utilizing expansion slots, users can upgrade their systems to meet new demands or leverage newer technologies without replacing the entire motherboard.

Sockets for connecting hard drives, ports for USB devices, and connectors for external power sources serve different purposes. Hard drive sockets are specifically designed for storage devices, USB ports allow for external peripherals, and power connectors are utilized to supply electrical power to components. Each of these has specific roles that do not relate to the addition of expansion cards.