- a waste-discharging tubule with an external excretory pore, found in many invertebrates, as in worms, mollusks, etc.
- any of the excretory tubules of the pronephros of a vertebrate embryo
Origin of nephridiumModern Latin ; from Classical Greek nephridion, diminutive of nephros, kidney: see nephro-
- A tubular excretory organ in many invertebrates, such as mollusks and earthworms.
- The excretory organ of a vertebrate embryo from which the kidney develops.
Origin of nephridiumnephr(o)– + Latin -idium, diminutive suff. (from Greek -idion).