1. A tubular excretory organ found in many invertebrate animals, such as annelids and mollusks, that functions to remove waste products from the body.
Usage: biology; zoology; plural: nephridia

Examples

• The earthworm uses its nephridia to filter waste from its body cavity.
• Each segment of an annelid typically contains a pair of nephridia.
• The nephridium opens to the outside through a small pore called the nephridiopore.
• In mollusks, nephridia help maintain water and salt balance.
• Scientists study nephridia to understand how invertebrates regulate their internal environment.