PHIAL is a 5 letter word that starts with P.

1. \Ley"den phi"al\ (f[imac]"al).(Elec.)
   A glass jar or bottle used to accumulate electricity. It is
   coated with tin foil, within and without, nearly to its top,
   and is surmounted by a brass knob which communicates with the
   inner coating, for the purpose of charging it with
   electricity. It is so named from having been invented in
   Leyden, Holland.
   
   

2. \Phi"al\, n. [F. fiole, L. phiala a broad, flat, shallow
   cup or bowl, Gr. ?. cf. {Vial}.]
   A glass vessel or bottle, especially a small bottle for
   medicines; a vial.
   
   

3. \Phi"al\, v. t. [imp. & p. p. {Phialed}; p. pr. & vb. n.
   {Phialing}.]
   To put or keep in, or as in, a phial.
   
         Its phial'd wrath may fate exhaust.      --Shenstone.