A "12-gauge" refers to a specific size of shotgun ammunition, commonly used in firearms. The term "gauge" indicates the diameter of the shotgun barrel, with a lower number representing a larger bore. A 12-gauge shotgun is versatile and can be used for various purposes, including hunting, sport shooting, and home defense. The 12-gauge shotgun is popular due to its wide availability and effectiveness. It can fire different types of shells, such as birdshot, buckshot, and slugs, making it suitable for various shooting scenarios. This adaptability contributes to its status as one of the most commonly used shotgun gauges worldwide.