Main Entry: ne·phrid·i·um

Pronunciation: \ni-ˈfrid-ē-əm\

Function: noun

Inflected Form(s): plural -ia \-ē-ə\

: 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 and discharging at the other end on the exterior of the body, is often lengthened and convoluted, and has glandular walls

[nephridium illustration]

—ne·phrid·i·al \-ē-əl\ adjective