What is the origin of the term "Devil Dog"?

The term "Devil Dog" has its origins from World War I, specifically during the Battle of Belleau Woods in 1918. German soldiers used the term to describe the tenacity and fierce fighting spirit of the U.S. Marines as they fought valiantly in that brutal conflict. The Germans were reportedly impressed and somewhat terrified by the Marines' relentless nature, leading them to liken the Marines to ferocious dogs of hell. This nickname, reflecting the bravery and ferocity of the Marines, has since become a point of pride within the Marine Corps community, symbolizing the courage and tenacity that define the Corps. The term has endured over the decades, further embedding itself into the identity of those who serve as United States Marines.