How did Marines earn the nickname "Devil Dog"?

The nickname "Devil Dog" for Marines originated during the battle of Belleau Wood in June 1918. During this significant World War I engagement, U.S. Marines fought fiercely against German forces, demonstrating exceptional courage and tenacity. The Germans referred to the Marines as "Teufel Hunden," which translates to "Devil Dogs," indicating their fierce, dogged fighting spirit in the face of overwhelming odds. This nickname was a testament to the Marines' reputation for resilience and ferocity in combat, and it has since become a point of pride and identity within the Marine Corps. The context of the battle solidified this name in the annals of Marine Corps history, making it a well-remembered and cherished moniker among Marines.