Master's degree.Here is the defination from the Wikipedia:A master's degree (from Latin magister) is an academic degree awarded by universities upon completion of a course of study demonstrating a mastery or high-order overview of a specific field of study or area of professional practice.[1] Within the area studied, graduates are posited to possess advanced knowledge of a specialized body of theoretical and applied topics; high order skills in analysis, critical evaluation, or professional application; and the ability to solve complex problemsand think rigorously and independently. The master's degree may qualify the holder to teach at a college or university in certain disciplines.Thus, the quick and simple answer is : master's degree; or you can use "master degree".