Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun rubidium

1 sense of rubidium

Sense 1
rubidium, Rb, atomic number 37 -- (a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite)
       => metallic element, metal -- (any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.)