Meaning of the Sanskrit Word: puresu

  pureṣu—holy places like Ayodhyā, Dvārakā and Mathurā    SB 3.1.18
  pureṣu—at those three residences occupied by the demons    SB 7.10.57
  pureṣu—within these residential places or bodies    SB 7.14.37

Can't find any compound Sanskrit words containing puresu.