oxygenator Syllabification: (ox·y·gen·a·tor)Pronunciation: /ˈäksəjəˌnātər/Definition of oxygenator noun Medicine an apparatus for oxygenating the blood. an aquatic plant that enriches the surrounding water with oxygen, especially in a pond or aquarium. oxygenator in other Oxford dictionaries Definition of oxygenator in the British & World English dictionary