köken: From Middle High German mōntac, māntac, from Old High German mānotag (9th c.), māntag (12th c.), from Proto-West Germanic *mānini dag (“day of the moon”), equivalent to Mond + Tag. Compare Low German Maandag, Dutch maandag, English Monday, Danish mandag.
köken: Inherited from Volga Bulgar, which is likey from Proto-Turkic *tog- (“to be born”). Related to dialectal Bashkir and Tatar туган күн (tuğan kün, “Monday; lit. birth day”), Eastern Mari шочмо (šočmo, “Monday; lit. birth day”). Perhaps from Volga Bulgar *طوطوى كوان (tawtuwi küwen).
köken: From Hellenistic Koine Greek Δευτέρα (Deutéra) from δεύτερος (deúteros, “second”) with ellipsis of the feminine noun ἡμέρα (hēméra, “day”): "the second day after Saturday".
Monday (now generally considered the first day of the week in non-religious contexts in Sweden)
çekim: çoğul måndagar · tamlayan måndags
köken: From Old Swedish mānadagher, from Old Norse mánadagr, from Proto-West Germanic *mānini dag, a calque of Latin dies lunae (“day of the moon”), equivalent of måne (“moon”) + dag (“day”). Cognate with Norwegian Bokmål mandag, Norwegian Nynorsk måndag, Danish mandag, Icelandic mánudagur, Faroese mánadagur, Finnish maanantai, English Monday, German Montag and Dutch maandag.
From Middle Dutch manendach, maendach, from Old Dutch *mānendag, from Proto-West Germanic *mānini dag (“day of the moon”). Compare Low German Maandag, West Frisian moandei, German Montag, English Monday, Danish mandag.