noun.
A crystalline amino acid, C4H8N2O3, found in many proteins, and present in large amounts in some plants, such as asparagus, that is easily hydrolyzed to aspartic acid.
the GNU version of the Collaborative International Dictionary of English
noun.
A white, nitrogenous, crystallizable substance, C4H8N2O3+H2O, found in many plants, and first obtained from asparagus. It is believed to aid in the disposition of nitrogenous matter throughout the plant; -- called also altheine.