In Yamaha motorcycles, "FZ" typically stands for "Four-Stroke, Zero Valve." It is a series designation used by Yamaha for their line of naked sport bikes. The FZ series is known for its aggressive styling, performance-oriented features, and a focus on delivering an exhilarating riding experience.
It's worth noting that Yamaha has used the "FZ" designation for various motorcycle models over the years, and the specific meaning of the acronym may have evolved or varied across different models and regions. However, the most common interpretation of "FZ" is "Four-Stroke, Zero Valve."