nə̇ˈfridēəm noun
( plural nephrid·ia -ēə)
Etymology: New Latin, from nephr- + -idium
1. : an excretory organ that is characteristic of various coelomate invertebrates (as annelid worms, mollusks, brachiopods, and some arthropods), occurs paired in each body segment or as a single pair serving the whole body, typically consists of a tube opening at one end into the coelom by a nephrostome and discharging at the other end by a nephridiopore on the exterior of the body, is often lengthened and convoluted, and has glandular walls
2. : any of various primarily excretory structures ; especially : nephron