What are blinds?

They are called blinds because they block or reduce sunlight penetration through windows. A blind typically has slats. They are made either vertical or horizontal that can be rotate for maximum privacy and  light control. Vertical blinds function, is similar to a curtain or drapes that can be open from one side ( Right or Left) and stack on one side of a window or they can be open from center and stack on both sides of a window.
Horizontal blinds are usually operated by a cord and can be completely up or down, still allow you to control the light and privacy.