Lack of a good nights sleep is a major problem in the world today.
This makes it great fodder for public speakers. However, what may seem a wonderful tidbit of information may get you in trouble.
The saying sleep tight is the fodder of of many tour guides. They will explain how beds with interwoven ropes supported the mattress. As the ropes would sag, tightening would be required. Thus the phrase was born, sleep tight. At least that is what they say.
Here it the problem. There is no historical proof that the phrase sleep tight means that.
It is most likely a verbal legend. All we know for sure is that rope were the support for the mattress.
The wordsmiths who study this will tell you that the saying “sleep tight” has its origins in the year 1886. That means it is not nearly as old as the beds. It is therefore, unlikely to have the implied meaning.
Additionally, the word “tight” was used to mean “soundly” in the 18th and 19th centuries.
So if you want to sleep soundly, make sure what you say is sound, tight and accurate.
Avoid perpetuating verbal legends.