Tetrinic \Te*trin"ic\, a. [See {Tetra-}.] (Chem.)
Of, pertaining to, or designating, a complex ketonic acid,
{C5H6O3}, obtained as a white crystalline substance; -- so
called because once supposed to contain a peculiar radical of
four carbon atoms. Called also {acetyl-acrylic acid}.
[1913 Webster]