Oust
The Oust is a river in Brittany , France , right tributary of the Vilaine . 
<triplet> Oust <subj> river <obj> instance of <subj> Vilaine <obj> mouth of the watercourse <triplet> Brittany <subj> France <obj> country <triplet> Vilaine <subj> Oust <obj> tributary <subj> river <obj> instance of