Erik (top) and Charles (bottom) sleeping tight. Two gray and white cats asleep atop a cat tree.
15 November 2021
People often say good night, sleep tight to those who are retiring for the evening, but why sleep tight? The meaning is obvious from the context, to sleep soundly and well, but tight usually means constricted or securely closed, and it’s not generally used adverbially. Fortunately, a look at the history of the word provides the answers. It comes out of an older adverbial use of tight with influence from the old miasma theory of disease.
Tightly in the sense of soundly or well dates to the turn of the seventeenth century. We see it in Ben Jonson’s play Every Man in His Humor, which was first performed in 1598, although the published script comes from 1601. In this passage the character of Giuliano is deploring his brother’s bad behavior, and when he says he shall heare on't, and that tightly too, that means he will give his brother a good talking to:
These are my brothers consorts these, these are his Cumrades, his walking mates, hees a gallant, a Caueliero too, right hangman cut, God let me not liue, and I could not finde in my hart to swinge the whole nest of them, one after another, and begin with him first, I am grieu'd it should be said he is my brother, and take these courses, well he shall heare on't, and that tightly too, and I liue Ifaith.
By the late eighteenth century, we see tight being used adverbially in the same sense. From James Fisher’s 1790 poem The Ale Wife’s Dying Advice:
When they grew doited wi’ the drink,
An’ scarce could either gang or wink,
But lie or tumble o’er a bink,
I charg’d them tight,
An’ gart them pay o’ lawing clink,
Mair than was right.
(When they grew impaired with the drink, and scarcely could either go or sleep, but lie or tumble over a bench, I charged them tight, and made them pay more coin than was owed for the boozing.)
The phrase sleep tight, meaning sleep soundly, pops up in North America in the latter half of the nineteenth century. The earliest use that I know of is in a 15 May 1866 diary entry by Susan Bradford Eppes:
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.
Another early use is in an 1873 poem titled G’anpa’s Nap, about an old man pretending to be asleep on his front porch while his grandchildren play around him:
“G’anpa, see! we’ve got some posies—
Nicest ones you ever saw!
Mamma gave us all these roses;
Why don’t you wake up, G’anpa?”“Guess he’s sleep tight,” whispered Gracie;
So they sat down side by side,
Softly playing there, till Daisey
Clapped her little hands and cried.”
And the next year we get this letter, purporting to be from Scottish heather to American trailing arbutus, printed in the Iowa State Register of 5 June 1874:
An’ noo we mann bid ye a lang fareweel while ye tak’ yer summer rest. May ye sleep tight an’ ha’e money happy dreams.
Since plants don’t write letters to one another, this is clearly a fiction invented by the newspaper editors, and one should not read the faux Scottish dialect as being any kind of clue as to the phrase’s origin.
The origin of sleep tight is really quite straightforward. It only seems odd because, other than this phrase, we don’t use tight in this adverbial sense anymore. Sleep tight probably only survives because of the rhyme with good night.
But there is one twist that probably influenced the use of sleep tight, and that is the miasma theory of disease. Prior to the advent of the germ theory of disease, it was commonly thought that many diseases were caused by bad or foul air, miasma. This belief was popular well into the nineteenth century. In her 1860 Notes on Nursing, Florence Nightingale advises parents not to keep the nursery tight shut up. This advice is repeated, often verbatim, many times throughout the latter half of that century:
That which, however, above all, is known to injure children seriously is foul air, and the most seriously at night. Keeping rooms where they sleep tight shut up is destruction to them.
Of course, here the word tight is modifying shut up, but it could easily be re-analyzed as modifying sleep. While not the direct origin of the phrase sleep tight, repeated reading of the two words side-by-side probably had an influence on the phrase’s coinage and popularity.
Finally, the notion, often spread by tour guides of Elizabethan houses and frequently seen on the internet, that sleep tight comes from the fact that Elizabethan beds had a foundation consisting of a rope net, and when the bed began to sag, one would tighten the net, is simply not true. Beds were once made this way, but that has nothing to do with the phrase, which comes along centuries later.
Sources:
Eppes, Susan Bradford. Through Some Eventful Years. Macon, Georgia: J.W. Burke, 1926, 328. HathiTrust Digital Archive.
Fisher, James. “The Ale Wife’s Dying Advice.” Poems on Various Subjects. Dumfries (Scotland): Robert Jackson, 1790, 61. Eighteenth Century Collections Online (ECCO).
Jonson, Ben. Every Man in His Humor (1598). London: Walter Burre, 1601, 1.4, sig. D2v. Early English Books Online (EEBO).
“A Letter from the Heather of Scotland to the Trailing Arbutus of America.” Iowa State Register, 5 June 1874, 3. Readex: America’s Historical Newspapers.
Nightingale, Florence. Notes on Nursing. Boston: William Carter, 1860, 96. HathiTrust Digital Archive.
Olmes, Elizabeth. “‘G’anpa’s’ Nap.” Zion’s Advocate (Portland, Maine), 17 December 1873, 4. Readex: America’s Historical Newspapers.
Oxford English Dictionary, second edition, 1989, s.v. tight, adj. adv. and n.2, tightly, adv.
Martin, Gary. “Sleep Tight.” The Phrase Finder, n.d.
Image credit: David Wilton, 2021. Licensable under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.