Emily Dickinson Lexicon

NUN'DI-NAL, a. [L. nundinalis, from nundinæ, a fair or market, quasi novem-dinæ, every nine days.]

1. Pertaining to a fair or to a market day.
2. A nundinal letter, among the Romans, was one of the eight first letters of the alphabet, which were repeated successively from the first to the last day of the year. One of these always expressed the market days, which returned every nine days.