What is the medical root that refers to the renal pelvis?

The root that refers to the renal pelvis is "Pyel/o." This term is derived from the Greek word "pyelos," which means basin or pelvis. In a medical context, it specifically pertains to the renal pelvis, which is the part of the kidney that collects urine before it moves to the ureter. This root is frequently used in various medical terms related to kidney function and conditions associated with the renal pelvis.

For example, "pyelonephritis" denotes an infection of the renal pelvis and kidney tissue, highlighting the importance of the term in clinical language.

The other roots provided, while they relate to the urinary system, denote different structures: "Nephro" relates to the kidneys, "Uretero" refers to the ureters, and "Cyst/o" pertains to the bladder. Therefore, the specificity of "Pyel/o" makes it the correct choice for referring to the renal pelvis.