The 4th Infantry Division is a modular division of the U.S. Army based at Fort Carson. It is composed of three organic brigade combat teams (i.e., Stryker, infantry, and armored), and one Combat Aviation Brigade. The 4th Infantry Division's official nickname, "Ivy", is a play on words of the Roman numeral IV or 4. Ivy leaves symbolize tenacity and fidelity, which is the basis of the division's motto: "Steadfast and Loyal." The second nickname, "Iron Horse," has been adopted to underscore the speed and power of the division and its soldiers.