Blinder (noun)

1. A device placed on a horse's head to prevent it from seeing to the side and becoming distracted during a race.
2. A device or material used to obstruct or block the view, or to obscure or conceal something.

Origin:

The origin of the word blinder is uncertain, it may have come from the word "blind" meaning to impede visibility or perception. it is first recorded in english in the 19th century.

Examples:

1. The horse was fitted with blinkers to keep its focus on the race.
2. The blinder was used to obscure the building's view of the construction site.
3. The blinder was used to block the sun's glare on the computer screen.
4. He put on the blinder to block out the distractions.
5. The blinder was used to obscure the view of the unwanted visitors.