A memory module is a small circuit board that contains memory chips used in computers and other electronic devices. It serves as a temporary storage area for data that the processor needs to access quickly. The most common type of memory module is RAM (Random Access Memory), which allows for fast read and write operations. Memory modules come in various forms, such as DIMM (Dual Inline Memory Module) for desktops and SO-DIMM (Small Outline DIMM) for laptops. They are essential for a computer's performance, as they enable multitasking and improve the speed of applications by providing quick access to frequently used data.