From WikiPilipinas: The Hip 'n Free Philippine Encyclopedia
A barangay is the smallest administrative unit, and several barangays comprise a municipality. Barangays however, are still divided into puroks, sitios and sonas (zones). The smaller section of a barangay is called a sitio or purok. Purok is a small community which usually consists small clusters of households. A purok leader/president is a person who leads the community and is often a member of the barangay council. The purok leader has his own set of officers who represents the whole purok.