ultimándolas: ending them

último: last

una: a

Unión: name given to Argentina by a constitution made by unitarios: Provincias Unidas del Río de la Plata

unitario: one of the two contending political groups since independence and during civil war (the other: federales).

Uruguay: one of two big rivers that form Río de la Plata. It goes from north to south. The eastern side is Brasil and Uruguay (Republic of) in the south. The western side is Argentina