‖ podionZool.|ˈpɒdɪɒn| Pl. podia. [mod.L., a. Gr. πόδιον: see podium.] One of the tube-feet of an echinoderm. 1900E. R. Lankester Treat.Zool. iii. 291 Water from the reservoir or ampulla is driven into the podion, and the tube-foot is thus rendered tense and rigid.