köken: From Middle High German donerstac, from Old High German donarestag, thonarestag (11th c.), from Proto-West Germanic *Þunras dag (“day of the thunder god”). Compare Bavarian Dunnersdåg, Low German Dunnersdag, Dutch donderdag, West Frisian tongersdei, English Thursday, Danish torsdag.
köken: From Middle French cinq, from Old French cinc, from Vulgar Latin cīnque, dissimilation of Classical Latin quīnque (“five”), from Proto-Italic *kʷenkʷe, from Proto-Indo-European *pénkʷe, cognate with Portuguese and Spanish cinco, Italian cinque. Doublet of punch.
aile: cinq à sept, cinq cents, cinq sur cinq, cinquante, cinquième
köken: Morphologically besh + -inchi. Cognates include Turkish beşinci, Kyrgyz бешинчи (beşinci), Turkmen bäşinji, Kazakh бесінші (besınşı) and Azerbaijani beşinci.
köken: From Volga Bulgar كجن ارن كون (kⁱçⁱn ernᵉ k^üw^ēn, “Thursday”). Literally “small week day” in Volga Bulgar. Cognate to Karaim кичиэйнэкүн. Probably the result of a Bulgar-Cuman sprachbund. See also Volga Bulgar حىان كوان (xyân kön, “Wednesday”), a cognate of Karaim къанкүн (kankün, “Wednesday”).
köken: From Hellenistic Koine Greek Πέμπτη (Pémptē) from πέμπτος (pémptos, “fifth”) with ellipsis of the feminine noun ἡμέρα (hēméra, “day”): "the fifth day after Saturday".