From Proto-Italic *argentom, from Proto-Indo-European *h₂r̥ǵn̥tóm.
So, the river bordering what is now Argentina was dubbed the River of Silver, and a Portuguese explorer called Lopo Homem was one of the first to associate this territory with silver, marking it on a map in 1554 as “Terra Argentea” – Land of Silver. The route of this is the Latin term “argentum” meaning silver. The first mention of the name Argentina appeared in a poem in Spain in 1602, and subsequently in 1776, the area which would now comprise of Argentina, Paraguay, Bolivia and Uruguay was officially named the Virreinato del Río de la Plata, or the Viceroyalty of the Rio de la Plata. When the country’s constitution was written in 1826, the country was called the Republic of Argentina, and remains so today. So there you have it! Now you know how Argentina got its name.