plural of masterclass

Possible to master; able to be mastered.

Someone who has undergone a mastectomy.

plural of master-at-arms

plural of master chief petty officer

plural of master sergeant

(UK, Navy) A warrant officer or chief petty officer responsible for discipline aboard a naval ship.

(Canada, Navy) A non-commissioned officer in the Canadian Forces Maritime Command, ranking above leading seaman and below petty officer second class.

plural of master seaman

(US, Navy) A non-commissioned officer in the United States Navy and United States Coast Guard, ranking above senior chief petty officer.