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 prator 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 licet agi.
These dies fasti were noted in the kalender 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 kalender thus; F. P. fastor primo, where justice might be demanded during the first part of that day.