isomere
 同質異能素
 I·so·mere n.  Zool.
 1. A homologous or corresponding part or segment.
 2.  Chem. same as Isomer. [archaic]
 Note: ☞  Formerly the term isomeric applied also to comopounds having the same percentage chemical composition, even if the number of atoms in a molecule differed.  In the 1913 dictionary isomeric was defined as:
 “Having the same percentage composition; -- said of two or more different substances which contain the same ingredients in the same proportions by weight, often used with with. Specif.: (a) Polymeric; =\i. e., having the same elements united in the same proportion by weight, but with different molecular weights; as, acetylene and benzine are isomeric (polymeric) with each other in this sense. See Polymeric. (b) Metameric; i. e., having the same elements united in the same proportions by weight, and with the same molecular weight, but with a different structure or arrangement of the ultimate parts; as, ethyl alcohol and methyl ether are isomeric (metameric) with each other in this sense. See Metameric.”\=
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