metamerism

UK: /mɪˈtæməˌrɪzəm/ US: (mə tam′ə riz′əm)

WordReference Random House Unabridged Dictionary of American English © 2025

me•tam•er•ism  (mə tam′ə riz′əm), n. 

1. [Zool.]
   • division into metameres, the developmental process of somite formation.
   • existence in a metameric state.
2. Chemistry isomerism resulting from the attachment of different groups to the same atom, as C₂H₅NHC₂H₅ and CH₃NHC₃H₇.

• 1840–50; (in def. 1) metamere + -ism; (in def. 2) meta- + (iso)merism

Collins Concise English Dictionary © HarperCollins Publishers::

metamerism / mɪˈtæməˌrɪzəm/ noun

1. Also called: metameric segmentation, segmentation the division of an animal into similar segments (metameres). In many vertebrates it is confined to the embryonic nervous and muscular systems
2. a type of isomerism in which molecular structures differ by the attachment of different groups to the same atom, as in CH₃OC₃H₇ and C₂H₅OC₂H₅