1630s, "any sticky substance," from Middle French gluten (16c.) or directly from Latin gluten "glue" (see glue (n.)). Used 16c.-19c. for the part of animal tissue now called fibrin; used since 1803 of the nitrogenous part of the flour of wheat or other grain; hence glutamic acid (1871), a common amino acid, and its salt, glutamate.
gluten glu·ten (glōōt'n)
n.
A mixture of insoluble plant proteins occurring in cereal grains, chiefly corn and wheat, used as an adhesive and as a flour substitute.