In the context of Harley-Davidson motorcycles, FLH stands for "Full Dresser, Electra Glide with a High-performance engine." The FLH designation is used to classify a specific line of touring motorcycles produced by Harley-Davidson. The FLH models are known for their large size, comfortable riding features, and powerful engines. The "F" in FLH represents the large frame, while "L" signifies the Big Twin engine, and "H" indicates a high-performance engine variant. Overall, FLH motorcycles are designed for long-distance cruising and are often associated with Harley-Davidson's touring and luxury touring lineup.