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-on¹

suff.

a. A discrete, small unit, such as a subatomic particle: baryon.

b. A property of a physical system when quantized as a particle: phonon.

2. A sequence of nucleotides or region of DNA: codon.

[From (ELECTR)ON (influenced by Greek -on, neuter of -os, n. and adj. suff., and -on, neuter of -ōn, n. and adj. suff.)]

-on²

suff.

Inert gas: radon.

[New Latin, from (ARG)ON.]

-on³

suff.

A chemical compound that is not a ketone or a compound that contains oxygen in a carbonyl group: parathion.

[Alteration of -ONE.]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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