hydronephrosis

This is a specialized medical term used primarily in clinical settings, such as urology and nephrology. It describes a pathological state rather than a disease itself, often serving as a clinical sign of an underlying issue like kidney stones, tumors, or congenital malformations.

As a medical condition describing a specific physiological state of organ swelling, the term is treated as an uncountable noun. It does not have a plural form in standard medical discourse; instead, clinicians specify whether the condition is unilateral (affecting one kidney) or bilateral (affecting both kidneys) to indicate the extent of the involvement.