Definition - What does 5.25 Inch Floppy Disk mean?
The 5.25-inch floppy disk was the successor to the 8-inch floppy disk and served as the dominant portable storage medium during the late 1970s and throughout the 1980s. It was developed in 1976 and was similar in capacity to the 8-inch floppy disk but used high-density media and recording techniques. Because of its lower price and smaller size, the 5.25-inch floppy disk quickly replaced its predecessor.
Techopedia explains 5.25 Inch Floppy Disk
Originally designed as a single-sided, low-density format with a storage capacity of 100 KB, the 5.25-inch floppy disk underwent many enhancements, including the introduction of a double-sided, high-density variant with a capacity of 1.2 MB. Like all floppy disks, the 5.25-inch floppy disk had a magnetic disk inside a case with a hole in the middle and was used with a dedicated disk drive capable of reading the magnetic data from the disk. However, the 5.25-inch floppy disk used a paper cover for the protection of the magnetic face of the disk and there was no other built-in protection. Similar to the 8-inch diskette, it had the same soft jacket and was flimsy. There was no additional robustness found in the 5.25-inch floppy disk.
The 5.25-inch floppy disk was available in different capacities: 360 KB low density, 160 KB single sided and 1.2 MB high density. This floppy disk usually had 10 sectors, and sometimes 16. The introduction of the 3.5-inch floppy disk, which had a larger storage capacity and a rigid case, made the 5.25-inch floppy disk obsolete.