The system by which astrologers divide the heavens into the houses. There are a number of systems in use today, the most widespread being Placidus, Koch and Equal House. Others, such as Regiomontanus, Campanus, Porphyry etc also have their dedicated adherents. Vedic and Hellenistic astrologers generally use Whole Sign Houses. It is a contentious area of astrology and some modern astrologers have abandoned houses altogether.