le·git·i·ma·tion \lə̇ˌjid.əˈmāshən\noun (-s) Etymology: Middle English legitimacioun, from Middle French or Medieval Latin; Middle French legitimation, from Medieval Latin legitimation-, legitimatio, from legitimatus (past participle of legitimare to legitimate) + Latin -ion-, -io -ion 1.: the act or process of making legitimate < English domestic law allowed legitimation by subsequent marriage — J.H.C.Morris > < the legitimation of money > 2.obsolete: legitimacy a