\Cos"sack\ (k?s"s?k), n. [Russ. kozak', kazak': cf.
Turk. kaz[=a]k.]
One of a warlike, pastoral people, skillful as horsemen,
inhabiting different parts of the Russian empire and
furnishing valuable contingents of irregular cavalry to its
armies, those of Little Russia and those of the Don forming
the principal divisions.