The only English weekday keeping a Roman god's name — Germanic peoples found no equivalent for Saturn.
The seventh day of the week in many cultures, following Friday and preceding Sunday.
From Old English 'sæternesdæg,' meaning 'day of Saturn,' a partial calque of Latin 'Sāturnī diēs' (day of Saturn). Unlike every other weekday, Saturday underwent no interpretatio germanica — the Germanic peoples found no native deity equivalent to the Roman god Saturn and simply borrowed his name directly. This makes Saturday the only English weekday that preserves a Roman deity's name rather than a Germanic one. Saturn was the god of agriculture, wealth, and time, and his festival Saturnalia — held in December — was one of Rome's most popular
Saturday is the only English weekday named after a Roman god rather than a Germanic one — the Anglo-Saxons simply could not find a Norse equivalent for Saturn, so they borrowed his name directly, making Saturday a lone Latin island in an otherwise Germanic week.