Furrinalia was a little-known festival in honour of Furrina, a Roman goddess of Etruscan origin. Disputes about her cult and the role she played are currently ongoing. Today, very little is known about both the celebration of the holiday and the goddess herself. It is only known that Cicero compared her to Furia (though probably only because of the similarity in name), and etymological studies seem to claim that Furrina was originally a deity associated with spring and water (after Plutarch). However, it was often associated with thieves (from the name furina meaning “thief”). It is also noted that her name may have been derived from the Latin words furvus or fuscus, meaning “dark” – which would indicate her as the goddess of darkness.
Varron mentions that Furrina’s day was a holy and non-working day (feriae publicae dies). The Romans themselves did not see much about this deity. One of the priests – flamen Furinalis – was assigned to her cult, which was worshipped in a sacred grove (lucus) on Janiculum Hill.