The second house is the second of the twelve houses of the horoscope, following the first around the wheel. It governs possessions, money, movable property, and material resources, and by extension the values a person holds and their sense of their own worth, what they own and what they treasure. It is a succedent house, the type that follows the angles; succedent houses are held to be of moderate strength, less forceful than the angular houses but more so than the cadent ones, and they are associated with the fixed, consolidating phase of each quadrant. These are the interpretive conventions of the astrological tradition for this division of the chart, in which the second house describes the substance a person gathers and holds after the self of the first house has been established.
In the Hellenistic scheme already traditional by the time Vettius Valens was writing around 175 CE and codified by Paulus Alexandrinus in 378, the second house carried a bleaker Greek name than its modern reputation for simple resources suggests, the Pyle Haidou or Gate of Hades, one of the places the tradition counted among the weaker and less fortunate of the twelve. No planet was said to rejoice here, unlike several of its neighbours, and the older texts treat it chiefly as a place of expense and outlay rather than of accumulation, the money that leaves through the gate as much as what enters it. The modern emphasis on the second house as simply what a person owns and values is a later softening of a division the ancient astrologers regarded with considerably more caution.
Sources A History of Western AstrologyNicholas Campion with Introduction to Astrology (Eisagogika)Paulus Alexandrinus