fumaric acid
noun
fu·mar·ic acid fyu̇-ˈmer-ik- 
-ˈma-rik-
: a crystalline acid C4H4O4 found in various plants or made synthetically
Example Sentences
Recent Examples on the Web Tests proved him right. Spraying experimental rice plants with artificial acid rain immediately cut their release into the soil of three relevant bacterial foodstuffs—fumaric acid, galactose and glucose. 
The Economist, 12 July 2018
The Economist, 12 July 2018 Word History
Etymology
International Scientific Vocabulary, from New Latin Fumaria, genus of herbs, from Late Latin, fumitory, from Latin fumus
First Known Use
circa 1864, in the meaning defined above
Medical Definition
fumaric acid
noun
fu·mar·ic acid fyu̇-ˌmar-ik-
: a crystalline acid C4H4O4 formed from succinic acid as an intermediate in the Krebs cycle