chymotrypsinPronunciation: /ˌkʌɪmə(ʊ)ˈtrɪpsɪn/Definition of chymotrypsin noun [mass noun] Biochemistry a digestive enzyme which breaks down proteins in the small intestine. It is secreted by the pancreas and converted into an active form by trypsin. Origin: 1930s: from chymo- (combining form of chyme) + trypsinchymotrypsin in other Oxford dictionaries Definition of chymotrypsin in the US English dictionary