Insidious invaders have infested the homestead museums and historic houses across our great land. No, they're not termites, rodents or carpenter ants, but instead innocent-looking docents and tour guides.

Beguilingly bedecked in bonnets and breeches, they cheerfully explain that the expression "sleep tight" arose because the ropes supporting the mattresses on old-fashioned beds were tightened to ensure comfortable sleep.

It's a charming word origin story, but, alas, completely untrue. This myth needs to be tucked in, put to sleep, de-"bunk"ed! You might even call it the Big "Lie."

For one thing, the earliest citation for the phrase "sleep tight" dates to May 2, 1866, when one Susan Eppes wrote in her diary, "All is ready and we leave as soon as breakfast is over. Goodbye little Diary. 'Sleep tight and wake bright,' for I will need you when I return."

Beds with rope supports have been in use since the 1400s, so if "sleep tight" did originate as a reference to them, why didn't "sleep tight" appear in print sooner? In criminology, this would be a case of the dog that didn't bark. In this instance, the hushed puppy is the essayist, poet or playwright who didn't write "sleep tight."

(In case you're wondering, the oft-added phrase "and don't let the bedbugs bite" was indeed inspired by old-time bedding. During the colonial era, mattresses were often filled with straw, feathers and corn husks — perfect homes for insects.)

So where DID "sleep tight" come from? Etymologist Evan Morris explains that the adverb "tight" was commonly used during the 1800s to mean "soundly" or "snugly." The Oxford English Dictionary dates this use of "tight" to 1790.

As James Breig observes in the Journal of Colonial Williamsburg, "'Tight,' as an adverb, means 'soundly,' 'snugly,' or 'closely,' so the expression means 'sleep well.' This use has lasted into our times, as anyone knows who has seen 'The Wizard of Oz,' Glinda the Good Witch tells Dorothy to 'keep tight' inside her ruby slippers. And who hasn't responded to a telephone caller asking for help by saying, 'Sit tight; I'll be right over.'"

Thus, as diarist Eppes might have phrased the eulogy for this fallacious origin, "Goodbye little False Etymology. Sleep tight and wake not — for I won't need you."

As for those deluded docents, Morris writes, "They constitute one of today's major 'vectors' or carriers of unfounded etymological 'urban legends.' ... Caveat viator — let the tourist beware."

Rob Kyff, a teacher and writer in West Hartford, Connecticut, invites your language sightings. His new book, "Mark My Words," is available for $9.99 on Amazon.com. Send your reports of misuse and abuse, as well as examples of good writing, via email to WordGuy@aol.com or by regular mail to Rob Kyff, Creators Syndicate, 737 3rd Street, Hermosa Beach, CA 90254.

Photo credit: Tama66 at Pixabay