HSV
Hue, Saturation, Value — similar to HSL but uses 'value' (max brightness) instead of lightness.
Definition
HSV (also called HSB) stands for Hue, Saturation, Value. Like HSL it uses Hue (0-360°) and Saturation (0-100%), but the third channel is Value (0% = black, 100% = pure color). Photoshop and most color pickers use HSV because it matches how artists think about color: pick a hue, then adjust saturation and brightness independently.
Formula
hsv(H, S%, V%). Conversion to RGB depends on which sextant of the hue wheel you're in.
Example
hsv(0, 100%, 100%) = pure red. hsv(276, 31%, 100%) = Mauve. Reducing value darkens to black; reducing saturation pulls toward white.