dosagePronunciation: /ˈdəʊsɪdʒ/Translate dosage | into German | into Italian | into Spanish Definition of dosage noun the size or frequency of a dose of a medicine or drug:a dosage of 450 milligrams a day [mass noun]:there are recommendations about dosage in elderly patients a level of exposure to or absorption of ionizing radiation. dosage in other Oxford dictionaries Definition of dosage in the US English dictionary