“Shades of black” commonly refers to a family of very dark neutrals. With zero saturation, the generated HSL ramp becomes grayscale, making it useful for comparing charcoal-like values with deeper blacks in a predictable way.
Using a near-black instead of absolute #000000 can reduce visual harshness in some interfaces, but the better choice depends on the surrounding palette and contrast target. Test the real pair rather than choosing a dark value by name alone.
Useful next steps
Try a specific color in the Tints and Shades Generator, or browse other shade families.