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actinium Definition

ac·tin·ium (ak tin′ē əm)

noun

a white, radioactive, metallic chemical element, the first member of the actinide series, found in pitchblende and other minerals or formed in reactors by the neutron irradiation of radium: symbol, Ac; at. no., 89

Etymology: ModL < actino- + -ium

Browse dictionary entries near actinium

  1. ‹ actinism
  2. ‹ actiniform
  3. ‹ actinide
  4. ‹ actinic rays
  5. ‹ actinic
  6. ‹ actinia
  7. ‹ acting
  8. ‹ actinal
  9. ‹ actin-
  10. ‹ actin
  1. actinium series ›
  2. actino- ›
  3. actinograph ›
  4. actinoid ›
  5. actinolite ›
  6. actinology ›
  7. actinometer ›
  8. actinomorphic ›
  9. actinomycete ›
  10. actinomycin ›