- Proto-Hind-Ewropaki ra *deuə- ("long in time") > *du-ro- ("dûri, lasting long")
- Proto-Aryaki ra
- Ewıstki: dūra- ("dûri")
- Farskiyo Kehen: dūra- ("dûri")
- Hotenki: dura- ("dûri")
- Farski: dūr ("dûri")
- Kurmancki: dūr ("dûri")
- Belucki: dūr ("dûri")
- Goranki: dur ("dûri")
- (Zazaki: dūrⁱ) Alfabeyê Ariki
- Sanskritki: dūrá- ("dûri")
- Yunanki: darón, din ("long lasting")
- Latinki: dūrāre ("to last")
- Horn, Paul. Dictionary of Persian Etymology (Strassburg, 1893),
- Watkins, Calvert. The American Heritage Dictionary of Indo-European Roots, 2nd ed., Houghton Mifflin Co., 2007. *Amazon.com ra, {{MacKenzie|MacKenzie P.123]],
- Julius Pokorny's Indo-European Etymological Dictionary
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