Nihonium (ニホニウム) is a chemical element. It is also named eka-thallium. It has the symbol Nh. It has the atomic number 113. It is a transuranium element. The name "nihonium" comes from the name of Japan in Japanese, 日本 (nihon).
Nihonium does not exist in nature, and can only be made artificially. It is made from the alpha decay of moscovium.
There are no known uses for nihonium. What nihonium looks like is not known because not enough has been made to see it with human eyesight. Based on trends in the Periodic Table it could be soft, silver color, very reactive metal like sodium.