gluten

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The mixture of proteins, including gliadins and glutelins, found in wheat grains, which are not soluble in water and which give wheat dough its elastic texture.
• noun Any of the prolamins found in cereal grains, especially the prolamins in wheat, rye, barley, and possibly oats, that cause digestive disorders such as celiac disease.

from The Century Dictionary.

• noun The nitrogenous part of the flour of wheat and other grains, which is insoluble in water.
• noun A glue-like animal secretion: for example, the sticky material secreted by swallows in nest-building.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Chem.) The viscid, tenacious substance which gives adhesiveness to dough.
• noun bread containing a large proportion of gluten; -- used in cases of diabetes.
• noun (Chem.) a vegetable proteid found in the seeds of grasses, and extracted as a dark, amorphous, earthy mass.
• noun (Chem.) a vegetable proteid found in the cereal grains, and extracted as an amorphous, brownish yellow substance.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a protein substance that remains when starch is removed from cereal grains; gives cohesiveness to dough