Webster’s Revised Unabridged Dictionary · 1913
Nephridium
Ne·phrid′i·um (·ŭm), n.; pl. Nephridia (#). [NL., fr. Gr. νεφρίδιος of the kidneys.] (Zoöl. & Anat.) A segmental tubule; one of the tubules of the primitive urinogenital organs; a segmental organ. See Illust. under Loeven's larva.