1. A fluid-filled cavity or reservoir in the brain or spinal cord, especially one containing cerebrospinal fluid.
Usage: anatomy; medical
2. A tank or underground chamber for storing water or other liquids.
Usage: archaic; technical

Examples

• The cisterna magna is the largest cerebrospinal fluid space in the brain.
• Doctors examined the cisterna to check for abnormal fluid accumulation.
• The patient's MRI revealed a cyst in the cisterna.
• In older buildings, a cisterna was often used to collect rainwater.
• The cisterna cerebellomedullaris connects the fourth ventricle to the subarachnoid space.