Source : Webster's Revised Unabridged Dictionary (1913)

Feria \Fe"ri*a\, n.; pl. {Feri[ae]}. (Eccl.)
   A week day, esp. a day which is neither a festival nor a
   fast. --Shipley.

Source : WordNet®

feriae
     See {feria}

feria
     n 1: 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"
     2: (in Spanish speaking regions) a local festival or fair,
        usually in honor of some patron saint
     [also: {feriae} (pl)]