prototherian Syllabification: (pro·to·the·ri·an)Pronunciation: /ˌprōtəˈTHirēən/ ZoologyDefinition of prototherian noun a mammal of the group Prototheria, which comprises the monotremes and their extinct relatives. adjective relating to or denoting prototherians. prototherian in other Oxford dictionaries Definition of prototherian in the British & World English dictionary
