- Rhizostomata Rhi`zo*stom"a*ta, n. pl. [NL., fr. Gr. ??? a root + ???, ????, a mouth.] (Zo["o]l.) A suborder of Medus[ae] which includes very large species without marginal tentacles, but having large mouth lobes closely united at the edges. See Illust. in Appendix. [1913 Webster]
The Collaborative International Dictionary of English. 2000.