Definition of "nihonium"

Japanese scientists behind the discovery of element 113, the first atomic element found in Asia - indeed, the first found outside Europe or the United States - have dubbed it "nihonium" after the Japanese-language name for their country.

2016 June 9, “First element discovered in Asia named 'nihonium', after Japan”, in Reuters‎

In January 2016 the International Union of Pure and Applied Chemistry (IUPAC) announced the discovery of four new elements, so completing the seventh row of the periodic table. They have since been named as nihonium, Nh, muscovium[sic], Mc, tennessine, Ts, and organesson[sic], Og. The procedures for naming new elements are clearly laid out by IUPAC.

2018, Mark Weller, Tina Overton, Fraser Armstrong, Jonathan Rourke, chapter 1, in Inorganic Chemistry‎, Oxford University Press, page 21

Researchers carefully choose the makeup of the beam and the target in hopes of producing a designer atom of the element desired. That’s how the four newest elements were created: nihonium (element 113), moscovium (115), tennessine (117) and oganesson (118) (SN Online: 11/30/16).

2019 February 27, Emily Conover, “Extreme elements push the boundaries of the periodic table”, in Science News‎