The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. The medical field that studies the kidneys and diseases of the kidney is called nephrology^[1]. The prefix nephro- meaning kidney is from the Ancient Greek word nephros (νεφρ?ς); the adjective renal meaning related to the kidney is from Latin r?n?s, meaning kidneys.

Parts of the kidney:
1. Renal pyramid
2. Efferent vessel
3. Renal artery
4. Renal vein
5. Renal hilum
6. Renal pelvis
7. Ureter
8. Minor calyx
9. Renal capsule
10. Inferior renal capsule
11. Superior renal capsule
12. Afferent vessel
13. Nephron
14. Minor calyx
15. Major calyx
16. Renal papilla
17. Renal column

More about kidney  found at Britannica.