instrumentāl

Noun

 * 1)  instrumental case

Usage notes
Instrumental case is a term used by some authors (including Viitso). Its suffix (-ks) is cognate with Estonian (-ks) and Finnish translative case endings (which is one of its functions in Livonian) with which a comitative function (Estonian affix ) has been syncretized. To avoid calling it "translative/comitative" it is called "instrumental" for short.