The -ette in cassette and diskette is a diminutive suffix. Cassette means little box. Casse is French for box. And thus Diskette means little disk, not disk in a protective case. IBM introduced the term to mean floppy disks smaller than their 8” floppy disks
Cassette is a French word, diskette is not. It even says that in your links. IBM used the word for the 8in floppies too. It’s a portmanteau of disk and cassette because IBM already made hard drives and these were portable and looked a little like a photography cassette.
I think both are technically just as valid, the use is only tradition
It started with branding. Like CD stands for CompactDisc which was a trademarked brand name using this logo.
Edit: I’m wrong. There is a patent for an optical disc that precedes CD and Laserdisc and uses the word Disc on the patent
That’s probably where disc started being used for optical storage. And disk remained being used for magnetic storage.
No one is short for discus and the other is short for diskette.
Disk comes from the Greek word Diskos. And Disc from
the French word Disque. Edit: You were right it comes from Latin DiscusDiskette means little disk. Floppy disks existed before diskettes.
Diskette comes from cassette which had been used in photography long before describing tapes and just meant that it had a built in protective case.
The -ette in cassette and diskette is a diminutive suffix. Cassette means little box. Casse is French for box. And thus Diskette means little disk, not disk in a protective case. IBM introduced the term to mean floppy disks smaller than their 8” floppy disks
https://www.etymonline.com/word/cassette
https://www.etymonline.com/word/diskette
Cassette is a French word, diskette is not. It even says that in your links. IBM used the word for the 8in floppies too. It’s a portmanteau of disk and cassette because IBM already made hard drives and these were portable and looked a little like a photography cassette.