The series of biochemical reactions in photosynthesis that do not require light to proceed, and ultimately produce organic molecules from carbon dioxide.
The energy from ATP (produced during the light reactions) drives the dark reactions of photosynthesis. The term dark reactions does not mean the reactions happen at night or that they require darkness. It means that the reactions can proceed regardless of the amount of light available. The term is only used to identify the dark reactions with the light reactions, which obviously require light.