Isomeric

[Sarah]

Having the same percentage composition; -- said of two or moredifferent substances which contain the same ingredients in the sameproportions by weight, often used with with. Specif.: (a) Polymeric;i. e., having the same elements united in the same proportion byweight, but with different molecular weights; as, acetylene andbenzine are isomeric (polymeric) with each other in this sense. SeePolymeric. (b) Metameric; i. e., having the same elements united inthe same proportions by weight, and with the same molecular weight,but which a different structure or arrangement of the ultimate parts;as, ethyl alcohol and methyl ether are isomeric (metameric) with eachother in this sense. See Metameric.