Definitions for "Lightless"
Destitute of light; dark.
without illumination; "came up the lightless stairs"; "the unilluminated side of Mars"; "through dark unlighted (or unlit) streets"
Keywords:  slat, visible, punch, tilted, downward
giving no light; "lightless stars `visible' only to radio antennae"
The hole in the blinds slats for the lift cords are punched at the back of the slat and are one half the size of a standard cord hole. When the blind is tilted downward in the closed position, the punch in the slat and the lift cord are not visible thus reducing the amount of light that comes through the blind.