Meaning of the Sanskrit Word: pitrn

  pitrn—forefathers    SB 3.3.26, SB 4.27.11
  pitrn—the forefathers    SB 3.32.2, SB 3.32.17
  pitrn—fathers    Bg 1.26
  pitrn—to ancestors    Bg 9.25
  pitrn—about the denizens of the Pitrloka planet    SB 1.16.31
  pitrn—the residents of Pitrloka    SB 2.3.8
  pitrn—the Pitas    SB 6.6.19
  pitrn—unto the forefathers    SB 7.14.15

Can't find any compound Sanskrit words containing pitrn.