nephridium
Concise Oxford English Dictionary © 2008 Oxford University Press:
nephridium /nɪˈfrɪdɪəm/
▶noun (pl. nephridia) Zoology (in many invertebrates) a minute tube open to the exterior for excretion or osmoregulation.
– derivatives
nephridial adjective.
nephridial adjective.
– origin C19: mod. L., from Gk nephrion (dimin. of nephros ‘kidney’) + the dimin. ending -idium.
'nephridium' also found in these Oxford entries:

