From Proto-Indo-European *dʰeiǵʰ-. Cognates include Sanskrit देग्धि (degdhi), Latin fingō, Avestan 𐬛𐬀𐬉𐬰𐬀 (daēza, “wall”), and Old Armenian դէզ (dēz).
τεῖχος • (teîkhos) (genitive τείχους or τείχεος); n, third declension;
- mound, earth works
- wall (especially one enclosing a town or city)
- fortified city
- fortification, castle
This inflection pattern originally had a sigma (i.e. τείχεσος), which was dropped early on in the history of Ancient Greek.
The irregular accentuation of this paradigm is explained by the fact that it is the contracted version of the above paradigm.