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

1 sense of neptunium

Sense 1
neptunium, Np, atomic number 93 -- (a radioactive transuranic metallic element; found in trace amounts in uranium ores; a by-product of the production of plutonium)
       => 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.)