Science & TechnologyGreek → English
Isotope
/ˈaɪsətoʊp/noun
One of two or more forms of an element with the same number of protons but different numbers of neutrons.
The Greek roots
ἴσος
ísos
equal, same
τόπος
tópos
place
Literally: “same place”
The story of the word
Frederick Soddy had found that chemically identical substances could differ in atomic weight and needed a name for them. Margaret Todd, a physician and novelist, suggested one over dinner in Glasgow in 1913: they occupy the same place in the periodic table, so call them isotopes. The name records exactly what the problem was, a single square on the table holding more than one thing.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 1913
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
Same family
isobarisothermtopographytopicutopia
In a sentence
Carbon dating relies on a radioactive isotope that decays at a known rate.