Capacitance is defined for electrostatics as the ratio of charge to voltage. Even for the simple case of two parallel discs in free space, there are over 25 associated capacitance terms identified in this work. Therefore, the simple free space disc capacitor has some underlying complexities. The various capacitance terms associated with two discs (or generally for two conductors in free space) are introduced and their interrelations defined. In particular, the relationships between the potential coefficient matrix, capacitance matrix and the Π and T capacitance networks are given in detail. Finally, the capacitance of two oppositely charged discs in free space is analysed for all separation distances. A collective work not available elsewhere is conveyed for the many capacitances and capacitance terms of two parallel discs in free space.