the.com/sleep mask

means A padded shade worn over the eyes to block light and trick your body into settling down for sleep.

from A straightforward compound of 'sleep' and 'mask' — no hidden backstory here. The idea of covering the eyes to sleep is ancient (think bandage-like wraps and silk coverings used for centuries), but the modern elasticized, padded version took off in the 20th century alongside eye-masks worn by travelers on trains and planes, where cabin lights and daylight windows made shut-eye hard to come by. The name just describes the job: it masks your eyes so sleep can happen.