1A member of a people of the Ob River basin in Western Siberia. Now usually called Khanty.
2The Ob-Ugrian language of this people; = "Khanty".
Of, relating to, or designating the Ostyaks or their language.
Late 17th century. From Russian ostjak from Ostyak āsjaχ (plural) people of the river Ob (singular asχo; compare Ās, name of the river Ob), reinterpreted as a singular after Russian -(j)ak, suffix forming nouns denoting a person from a particular place.