gen. Rib.; rare form of nom. plur. , an undulating , boiling , waving , tossing; a waving , heaving , billowy motion.

http://lila-erc.eu/data/lexicalResources/LewisShort/id/LexicalSense/n1404.0 an entity of type: LexicalSense

gen. Rib.; rare form of nom. plur. , an undulating , boiling , waving , tossing; a waving , heaving , billowy motion. 
gen. Rib.; rare form of nom. plur. , an undulating , boiling , waving , tossing; a waving , heaving , billowy motion. 

data from the linked data cloud