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").
word-forming element meaning "surgical removal," from Latinized form of Greek -ektomia "a cutting out of," from ektemnein "to cut out," from ek "out" (see ex-) + temnein "to cut" (from PIE root *tem- "to cut").
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<a href="https://www.etymonline.com/word/nephrectomy">Etymology of nephrectomy by etymonline</a>
Harper, D. (n.d.). Etymology of nephrectomy. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/nephrectomy