This week, we answer a question from Evelio in Colombia. He writes: Why is a sort of men's underwear called "long johns"? Thank you.-- Evelio, Colombia Dear Evelio, When I looked up the history of the term "long johns," I found it was first used in World War II by American soldiers. That got me thinking about other words and phrases the soldiers invented. Many words that we use today, or are considered slang terms, came from the soldiers in that war. World War II was fought in many areas, including Europe. Because parts of Europe get cold in winter, the U.S. military gave soldiers special under-clothing to help keep them warm. This under-clothing covered much of the body, even the arms and legs. The soldiers called it "long johns."