It is totally normal in the German language to use the word "usus" as a word which means "the use of something".
I could for example say "In our home it is usus to wash our hands before eating the meal."
It is as usual and norml, as I would say : "This text has a special ductus". The word "ductus" means "diction", or way of speech / writing (hope I've spelled it correctly).
So I could say "this texts has a special diction", and this would be the same.
