The process whose specific outcome is the progression of the kidney over time, from its formation to the mature structure. The kidney is an organ that filters the blood and/or excretes the end products of body metabolism in the form of urine. [ GOC:mtg_kidney_jan10 https://www.worldcat.org/search?q=bn%3A0721662544 GOC:dph https://www.worldcat.org/search?q=bn%3A0124020607 ]