ni·ho·ni·um (nē-hōnē-əm, nĭ-)
n. Symbol Nh
An artificially produced radioactive element with atomic number 113 whose most stable isotopes have a mass number of 286 and 285, with half-lives of approximately 20 seconds and 5.5 seconds, respectively.
[Japanese Nihon, Japan (from Old Japanese, from Middle Chinese ŋit-pən', literally “(Land of the) Rising Sun” (source of modern Mandarin Rìběn, Japan) : ŋit, sun, from Old Chinese *nit; akin to Tibetan ñi-ma and Burmese ne + pən', root, stalk, origin, from Old Chinese *pənʔ, from Proto-Sino-Tibetan *pul) + -IUM (so called because the element was first synthesized in 2004 by a research team at the Riken Institute in Japan). See Word History at Japan.]
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