nephrolithiasis (n.)

before vowels nephr-, word-forming element meaning "kidney, kidneys," from Greek nephros "a kidney" (plural nephroi), from PIE *negwhro- "kidney" (source also of Latin nefrones, Old Norse nyra, Dutch nier, German Niere "kidney").

before vowels, lith-, word-forming element meaning "stone, rock;" from Greek lithos "stone, a precious stone, marble; a piece on a game board," a word of unknown origin.

medical Latin word-forming element used in naming diseases, from Greek -asis, abstract noun suffix (often expressing "disease, morbid condition") from the aorist of verbs in -aein. The -i- is connective.