DNase Syllabification: (DNase)Pronunciation: /ˌdēˈenˌās, -ˌāz/Definition of DNase noun Biochemistry an enzyme that catalyzes the hydrolysis of DNA into oligonucleotides and smaller molecules. Also called deoxyribonuclease.Origin: 1940s: from DNA + -aseDNase in other Oxford dictionaries Definition of DNase in the British & World English dictionary