becquerel(Bq) The SI unit of radioactivity, being the activity of a nuclide that decays with an average of one spontaneous transition per second. The unit is named after the French physicist Antoine Henri Becquerel (1852–1908).

becquerel Symbol Bq. The SI unit of activity (see radiation units). The unit is named after the discoverer of radioactivity, A. H. Becquerel (1852–1908).

becquerel (bek-er-el) n. the SI unit of activity of a radioactive source, being the activity of a radionuclide decaying at a rate of one spontaneous nuclear transition per second. It has replaced the curie. Symbol: Bq.