FASTI, or Dies Fasti, also denoted court days. The word fasti fastorum, is formed of the verb fari, "to speak," because during those days the courts were opened, causes might be heard, and the praetor was allowed fari, to pronounce the three words, do, dico, addico: The other days wherein this was prohibited were called nefasti: thus Ovid,
Ille nefastus erit, per quem tria verba silentur:
Fastus erit, per quem lege licebit agi.
These dies fasti were noted in the calendar by the letter F: but observe, that there were some days ex parte fasti, partly fasti, partly nefasti; i. e. justice might be distributed at certain times of the day, and not at others. These days were called interfasti, and were marked in the calendar thus; F. P. fastos primo, where justice might be demanded during the first part of that day.