HSL stands for hue, saturation, and lightness. HSV stands for hue, saturation, and value. A third model, common in computer vision applications, is HSI, for hue, saturation, and intensity. Unfortunately, while typically consistent, these definitions are not standardized. HLS, high-level synthesis, is an automated design process that interprets an algorithmic description of a desired behavior and creates hardware that implements that behavior. HLV, high-level verification, is the task to verify ESL designs at high abstraction level. 🙂