1. The betrayal of allegiance toward one's own country, especially by committing hostile acts against it or aiding its enemies in committing such acts.
2. The betrayal of someone's trust or confidence.
[Middle English, from Anglo-Norman treson, from Latin trāditiō, trāditiōn-, a handing over; see TRADITION.]
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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:
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.