Nominalized inflectional morphemes

[sagehen]

Re: omnibus,Larry wrote:
....... it's more plausibly a dative plural........

Flanders&Swann apparently had the ablative also  in mind in their line in
"The London Omnibus" that went, more or less:  "to, at, for, with or by
everyone."
Speaking of Latin derivations, I remember our ninth grade Latin teacher, in
urgng us to recognize cognates, assuring us that Ferris  wheels were so
called because made of iron. She might more plausibly have related ferris
to the verb /fero, ferre/ as a carrying wheel, I suppose, and still been
wrong!
A. Murie