Which term is used for a horse with a solid coat and an irregular spotted pattern?

The term that describes a horse with a solid coat and an irregular spotted pattern is "Appaloosa." This breed is well-known for its distinct coat patterns, which can feature a combination of solid colors with varying sizes and distributions of spots. The spots often reflect a range of colors and can appear on different base coat colors, lending each Appaloosa its unique appearance.

In contrast to Appaloosas, "Piebald" refers specifically to a black-and-white color pattern, which is not applicable for a horse with a solid coat and irregular spots. "Overo" is a type of paint horse color pattern characterized by irregular patches that do not cross the back, but it doesn't specifically refer to solid coats. Lastly, "Spotted" is a general term that may not adequately define the specific breed characteristics associated with Appaloosas, which have specific genetic traits responsible for their unique coat patterns and color variations. Thus, Appaloosa is the most accurate term for a horse with a solid coat and irregular spots.