[po.lo.ni.um] n [NL, fr. ML Polonia] (1898): a radioactive metallic element that is similar chemically to tellurium and bismuth, occurs esp. in pitchblende and radium-lead residues, and emits an alpha particle to form an isotope of lead
POLONIUM
Meaning of POLONIUM in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012