Monday
Old English Mōnandæg ‘day of the moon’, translation of late Latin lunae dies ; compare with Dutch maandag and German Montag .
wiktionary
From Middle English Monday, Monenday, from Old English mōnandæġ(“day of the moon”), from Proto-West Germanic *mānini dag, a translation ( interpretātiō germānica) of Latin diēs Lūnae, equivalent to Moon + day. Compare Saterland Frisian Moundai(“Monday”), West Frisian moandei(“Monday”), German Low German Maandag, Moondag, Maondag(“Monday”), Dutch maandag(“Monday”), German Montag(“Monday”), Pennsylvania German Mundaag(“Monday”), Danish mandag(“Monday”), Swedish måndag(“Monday”), Norwegian Bokmål mandag(“Monday”), Norwegian Nynorsk måndag(“Monday”), Icelandic mánudagur(“Monday”), Finnish maanantai(“Monday”).
etymonline
Monday (n.)
second day of the week, Middle English monedai, from Old English mōndæg, contraction of mōnandæg "Monday," literally "day of the moon," from mona (genitive monan; see moon (n.)) + dæg (see day). A common Germanic name (compare Old Norse manandagr, Old Frisian monendei, Dutch maandag, German Montag). All are loan-translations of Late Latin Lunæ dies, which also is the source of the day name in Romance languages (French lundi, Italian lunedi, Spanish lunes), itself a loan-translation of Greek Selēnēs hēmera. The name for this day in Slavic tongues generally means "day after Sunday."
Yf cristemas day on A munday be,
Grete wynter þat yere ye shull see.
[proverb, c. 1500]
Phrase Monday morning quarterback is attested from 1932, Monday being the first day back at work after the weekend, where school and college football games played over the weekend were discussed. Black Monday (late 14c.) is the Monday after Easter day, though how it got its reputation for bad luck is a mystery (none of the usual explanation stories holds water). Saint Monday (1753) was "used with reference to the practice among workmen of being idle Monday, as a consequence of drunkenness on the Sunday" before [OED]. Clergymen, meanwhile, when indisposed complained of feeling Mondayish (1804) in reference to effects of Sunday's labors.
