English Etymology Borrowed from Latin reniculus. Noun reniculus (plural reniculi) (anatomy, cetology) One of the lobules of the kidney, especially in whales. 2015, Annalisa Berta, Marine Mammals: Evolutionary Biology:Each reniculus is like a small individual kidney with its own cortex, medulla, and calyx, and the duct from each small unit joins with others to form the ureter. LatinLoading content...Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads