Definition of the word sleep in

The phrase "sleep in" is a commonly used English idiom that refers to staying in bed and sleeping for an extended period, usually beyond one's usual waking time. The roots of this expression can be traced back to the early 20th century, particularly in the United States. The verb "sleep" has been used since the Old English period as a transitive verb, followed by the preposition "in." However, until the 1920s, "sleep in" was written in hyphens as "sleep-in" and commonly appeared in publications such as The New York Times and Time Magazine. The origin of the phrase is likely linked to the growing trend of sleeping in on weekends or holidays as a part of a desired sleep pattern known as "sleep hygiene." This practice is considered beneficial for one's overall health, as it helps in improving the quality and duration of sleep, thus making individuals more alert and productive during the week. Some sources also suggest that the term originated during the industrial era when factory workers, who used to live in dorms near their factories, were allowed to come to work late after sleeping overnight in their dormitories. In summary, "sleep in" entered the lexicon of the English language in the early 20th century, and its origins may be attributed to improving sleep hygiene or the factory dormitory culture.