(chemistry) Any of two or more compounds with the same molecular formula but with different structure.
(chemistry) Any diastereoisomer that has the opposite configuration at only one of the stereogenic centres.
(physics) Any of two or more atomic nuclei with the same mass number and atomic number but with different radioactive properties.
In stereochemistry, an epimer is one of a pair of diastereomers. The two epimers have opposite configuration at only one stereogenic center out of at least two.
A compound which is isomeric with another body or compound; a compound having the same chemical composition as another compound; a member of an isomeric series.
a compound that exists in forms having different arrangements of atoms but the same molecular weight
In chemistry, isomers are molecules or polyatomic ions with identical molecular formulas — that is, same number of atoms of each element — but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers.