SinginginSilence
Of what noun did you get Reus? The only thing that comes to my mind is Res Rei meaning thing. Or is it an idiomatic expression?
it's just another form of the latin word.
they change declension depending on their usage, like
hic, haec, hochttp://www.personal.kent.edu/~bkharvey/latin/morph/morprohc.htm