A molecule containing the same number and kind of atom groupings as another but in a different arrangement in space; the stereoisomers are not interconvertible unless bonds are broken and reformed, by virtue of which it exhibits different optic properties, e.g., as between d- and l-amino acids, 5α- and 5β-steroids. Cf.:isomer. [stereo- + G. isos, equal, + meros, part]
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ste·reo·iso·mer .ster-ē-ō-'ī-sə-mər, .stir- n any of a group of isomers in which atoms are linked in the same order but differ in their spatial arrangement
ste·reo·iso·mer·ic -.ī-sə-'mer-ik adj
ste·reo·isom·er·ism -ī-'säm-ə-.riz-əm n
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ster·eo·iso·mer (ster″e-o-iґso-mər) one of a group of compounds having a stereoisomeric relationship.Medical dictionary. 2011.