In English, Ruthenia is a geographical exonym for a cross-border region of Eastern Europe. It can refer to significantly different and even mutually exclusive areas, dependent on the historical period and subject.
The word "Ruthenia" originated as a Latin rendering of the region and people known originally as "Rus'" – the same root word as Russia. In European manuscripts dating from the 13th century, "Ruthenia" was used to describe Rus': the wider area occupied by the Ancient Rus' (commonly referred to as Kievan Rus'). This historical territory corresponds to modern Ukraine and Belarus, as well as western Russia. However, the geographical implications of "Ruthenia" and "Russia" began to diverge in meaning as early as the 14th century.
In modern usage, "Ruthenia" refers often to Red Ruthenia alone, or an even smaller region centred on Zakarpattia Oblast (the Transcarpathian administrative region) of south-western Ukraine. It is therefore strongly associated with areas inhabited by Rusyn minorities. Red Ruthenia also includes the former kingdom of Galicia (Halychyna (Halychyna; Rusyn: Галичина; ; , Galitsiya; ).