/ruy zoh"bee euhm/ , n. , pl. rhizobia /-bee euh/ . Bacteriol.
any of several rod-shaped bacteria of the genus Rhizobium, found as symbiotic nitrogen fixers in nodules on the roots of the bean, clover, etc.
[ rhizo- RHIZO- + Gk bí ( os ) life (see BIO-) + L -um n. suffix ]