"4 KB" refers to a unit of digital information storage that equals 4 kilobytes. A kilobyte is typically defined as 1,024 bytes, so 4 KB is 4,096 bytes. This amount of data can store a small text file, such as a short document or a few lines of code. In the context of computer memory, 4 KB is often used to describe the size of memory pages in operating systems. Many systems use this size for efficient data management, allowing for quick access and organization of information in RAM and other storage devices.