PRUDENTIAL is a 10 letter word that starts with P.

1. \Pru*den"tial\, a.
   1. Proceeding from, or dictated or characterized by,
      prudence; prudent; discreet; sometimes, selfish or
      pecuniary as distinguished from higher motives or
      influences; as, prudential motives. `` A prudential line
      of conduct.'' --Sir W. Scott.
   
   2. Exercising prudence; discretionary; advisory;
      superintending or executive; as, a prudential committee.
   
   

2. \Pru*den"tial\, n.
   That which relates to or demands the exercise of, discretion
   or prudence; -- usually in the pl.
   
         Many stanzas, in poetic measures, contain rules
         relating to common prudentials as well as to religion.
                                                  --I. Watts.