I mean, no one ever called it a “mini floppy”. I never heard that term until I visited this website, and I spent more than a decade using 5.25” floppies. I realize they are smaller than 8” floppies, but they were still called floppies.
"The latest news from Silicon Valley, now confirmed from its source, is the Shugart Associates Minifloppy ["minifloppy" is a Shugart trademark] disk drive for small systems."
This is about the new 5 1/4" floppies. I see the term used as late as in the Byte issue about the IBM PC in 1982, and possibly later. It wasn't before the 3.5" floppy arrived that the term completely fell out of use about the 5 1/4" floppy.
(Edit: Reworded slightly)
It lived on even longer in marketing and packaging. The image below is of a pack of HD 5,25" disks -- judging by the overall design of it I would wager it's from the very late 80s or early 90s. Still Mini Floppy Disks.
https://ae01.alicdn.com/kf/H881c0843bd37476aa487619ee0ad8c79...
It does call itself MD2-HD which is the abbreviation for Mini Disk, 2 sided, High Density. Mini disk here means 5.25".
3.5" disks were MF "Micro Floppy", as in MF2-DD or MF2-HD.
I guess it depends on which audience or circles you ran in. I'll admit to have not gotten into computing until 1981, and then as a teen, but in that time, at that place (US, South), in my audience... literally no one used the term "minifloppy".
And by "3.5" floppy arrived..." I'm using the phrase to mean in use by something the consumer might see and be able to buy; not "invented". I had an original 1984 Mac hot off the shelf as soon as it was available, and that's the "arrived" point for me.
And yes, people in general wouldn't use the term "minifloppy" in normal conversation (except, possibly, old-timers mostly used to "real" floppies, the 8" ones. But even I wouldn't, even though I - just barely - started using computers and floppies before the invention of 5 1/4" drives), you wouldn't say "Please hand me the minifloppy". Just ".. the floppy". You don't use a long term when a short will do.
But, as einr said, it lived on for longer in marketing and packaging.
This matches my experience, too. East Coast USA late 70s and early 80s. We called them disks, diskettes, and floppies. i didn't know anyone with the 8" variety, and 3.5" came later.
I never used an 8", but I have seen one firsthand. Friend of mine from high school had one as his father had some sort of older machine at home that used them. It looked (to me) comically large.
It may not be the colloquial name but it surely was used. And of course only knowing 5.25s and 3.5s, it sure looked weird that the bigger one was called "mini".
3.5 models were called "stiffy/stiffies" because they were, you know, stiffer than floppies.
80s and 90s South Africa.