isotopomer

Isomers having the same number of each isotopic atom but differing in their positions. The term is a contraction of 'isotopic isomer'. Isotopomers can be either constitutional isomers (e.g. CH2DCH=O and CH3CD=O) or isotopic stereoisomers [e.g. (R)- and (S)-CH3CHDOH or (Z)- and (E)-CH3CH=CHD].
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1132
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2211