History of Oceania

Why was it called World War 1 if not all countries were involved?

The term "World War" is more accurately understood when looking at the extent of countries and empires that declared war or became directly involved with military force. While not every single nation worldwide actively participated in hostilities, many were impacted due to geopolitical alliances, trade disruptions, economic fallout, and other consequences resulting from the widespread and prolonged nature of the armed conflict.