lipasePronunciation: /ˈlɪpeɪz, ˈlʌɪp-/Definition of lipase noun [mass noun] Biochemistry a pancreatic enzyme that catalyses the breakdown of fats to fatty acids and glycerol or other alcohols. Origin: late 19th century: from Greek lipos 'fat' + -aselipase in other Oxford dictionaries Definition of lipase in the US English dictionary