nephridial,a.Zool.|nɛˈfrɪdɪəl| [f. nephridi-um + -al1.] Pertaining or relating to a nephridium. 1888Rolleston & Jackson Anim. Life 462 The walls of the nephridial and viscero-pericardial sacs.Ibid. 463 The nephridial epithelium..is..longitudinally striated.