Original: Before the 20th century, the term 'Nordic' or 'Northern' was commonly used to mean Northern Europe in a sense that included the Nordic countries, European Russia, the Baltic countries (at that time Estonia, Livonia and Courland).
Simplified: Before the 19th century, the term 'Nordic' or 'Northern' was commonly used to mean Northern Europe in a sense that included the Nordic countries, European Russia, the Baltic countries (at that time Livonia and Courland) and Greenland.