PACHISI is a 7 letter word that starts with P.

1. \Pa*chi"si\, n. Commonly spelt Parchesi \Par*che"si\,
   

2. \Pa*chi"si\, Parchesi \Par*che"si\, n. [Hind., fr.
   pachis twenty-five, the highest throw in the game.]
   A game, somewhat resembling backgammon, originating in India.