metamerism

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

• noun The condition of having the body divided into metameres, apparent in certain animals only in the early embryonic stages of development.

from The Century Dictionary.

• noun In chem., a form of isomerism, that property of certain compound bodies by which they have the same chemical elements combined in the same proportion and with the same molecular weight, while differingin chemical properties.
• noun In zoology, a metameric condition; the state of being metameric; segmentation of the body of an animal along the primary or longitudinal axis, resulting in a series of more or less similar consecutive parts which are serially homologous. See metamere, antimere.

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

• noun (Biol.) The symmetry of a metameric structure; serial symmetry; the state of being made up of metameres.
• noun (Chem.) The state or quality of being metameric; isomerism due to different bonding patterns in two substances having the same molecular formula. Contrasted with steroisomerism or optical isomerism. Also, the relation or condition of metameric compounds.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology The segmentation of the body into similar discrete units
• noun colorimetry The matching of apparent color of objects with different spectral power distributions.
• noun chemistry structural isomerism