A 3.5-inch floppy disk is a type of data storage medium that was widely used from the 1980s to the early 2000s. It is a square, plastic disk encased in a protective shell, measuring 3.5 inches on each side. The disk can store up to 1.44 megabytes of data, making it suitable for saving documents, software, and other files. Floppy disks were commonly used in personal computers and were often inserted into a floppy disk drive for reading and writing data. Although they have largely been replaced by more advanced storage solutions like USB flash drives and cloud storage, floppy disks remain an important part of computing history.