feria

noun

1

(in Spanish speaking regions) a local festival or fair, usually in honor of some patron saint

2

a weekday on which no festival or holiday is celebrated

in the middle ages feria was used with a prefixed ordinal number to designate the day of the week, so `secunda feria' meant Monday, but Sunday and Saturday were always called by their names, Dominicus and Sabbatum, and so feria came to mean an ordinary weekday