1. A dark, often underground chamber used to confine prisoners.
2. A donjon.
[Middle English donjon, castle keep, dungeon, from Old French, keep, probably from Medieval Latin domniō, domniōn-, the lord's tower, from Latin dominus, master; see dem- in the Appendix of Indo-European roots.]
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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.