The story
- Proto-Indo-European*h₂erǵ-
- Proto-Indo-European*h₂ŕ̥ǵn̥tom
- Proto-Italic*argentom
- Latinargentum
- Latinargentīnu
- Spanishargentino
- SpanishArgentina
- EnglishArgentin(a)
- English todayArgentinian
From Argentin(a) + -ian.
Etymology from Wiktionary, CC BY-SA 4.0.