The chemical element (symbol Be) with an atomic number of 4; a soft silvery-white low density alkaline earth metal with specialist industrial applications. / (countable) An atom of this element.

plural of beryllium

(inorganic chemistry) A colourless, hygroscopic solid with the formula BeCl₂.

(inorganic chemistry) The hard binary compound of beryllium and carbon Be₂C

(inorganic chemistry) A nitride of beryllium, Be₃N₂.

(inorganic chemistry) A white, crystalline compound, BeO, used in semiconductors and in specialist ceramic applications.

(physics) The only stable isotope of beryllium, ⁹₄Be, having four protons and five neutrons

(physics) Having the electron configuration of beryllium