Science & TechnologyGreek → English
Isomer
/ˈaɪsəmər/noun
One of two or more compounds with the same atoms in the same numbers but arranged differently.
The Greek roots
ἴσος
ísos
equal, the same
μέρος
méros
part, share
Literally: “having equal parts”
The story of the word
Berzelius coined isomeric in 1830 for a result chemists found intolerable at the time: two substances with identical composition and completely different behaviour. The name concedes only the equality of the parts, which is exactly the point, since everything that distinguishes the two lies in the arrangement. Fulminate and cyanate were the pair that forced the issue.
- How it travelled
- Ancient Greek → scientific coinage → English
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
Same family
isotopeisoscelespolymerisobar
In a sentence
Two isomers of the drug exist, and only one of them does anything useful.