Definition above: "......It is easy to tell the biots apart from the rear fibers, as they are shorter, stiffer, and lay closer to the quill stem
Biots are nothing more or less than Barbs. They do lay closer to the stem (Quill) than the barbs on the back side. We should not confuse Biots, Barbs, Quill.
Term "rear Fibers" above are Barbs. Should not be confused. Our term Biots are one of the names given by tiers to front, stiffer (Plus many different qualities) from biots on other feathers. You can strip the front barbs off any stem (Quill) and use them as biots. Just would not get the same results because they are different. I suggest you try different feathers to obtain and use for biots on different flies. Might surprise you!
One needs to know what the feather we are talking about as to what is it's purpose to the bird. Is it for insulation? help in flight? helpful in incubation? Each feather on a bird has a specific usage, placed there by the Creator. I find it very interesting.
Due to marketing, $$$ etc, we find it confusing as tiers. Many terms thrown out and used improperly by those that want to sell us materials. Not always marketers but some tiers wanting to promote themselves or say a fly. I personally find no fault with this but it does get confusing. The article you posted the URL to is an excellent one on Biots but they call the Biot "nothing more than a fiber". It should be called a barb because that is what it is. Obviously the person that wrote the explanation was not up to speed on Prober nomenclature of a feather. Just a word game? Who really cares?
I'd say it really makes no difference, just tie and go Fishin.

Denny