·noun Illumination, or degree of illumination; as, the lightness of a room.
II. Lightness ·noun Absence of depth or of duskiness in color; as, the lightness of a tint; lightness of complexion.
III. Lightness ·noun The state, condition, or quality, of being light or not heavy; buoyancy; levity; fickleness; nimbleness; delicacy; grace.