It’s the bats that keep me awake.
Dear WD: A fellow member of the Copyediting Digest steered me to your web site when I queried my cohorts about the origin of “sleep tight.” I’ve looked in several sources and the best I found was a children’s nursery rhyme or song that included the line “Sleep tight and don’t let the bedbugs bite.” I’d appreciate any insight you might have on this phrase. — Julia DeGraf, Evanston, IL.
Bed bugs? Not in my house. When I was growing up, my parents used to tuck us away with “Sleep tight and don’t let the IRS bite.” Granted, it doesn’t fit as well as “bedbugs,” but it made more sense in our house and turned out to be sound advice for later life.
According to etymologist Eric Partridge, the catch phrase “sleep tight and don’t let the bedbugs bite” is the American version of a British “children’s goodnight” which differs only in that it specifies “fleas” as the critters to be avoided. Partridge traced the phrase back to the late 19th or early 20th century, although he speculates that it may actually be much older, since, he notes, “This is the type of phrase that … escapes the attention of lexicographers, even light-hearted ones.”
As to where “sleep tight” itself came from, the Oxford English Dictionary lists “tight” in this sense as a form of the adverb “tightly,” meaning “soundly.” Although this “tight” could once be applied to anything done thoroughly, the OED notes that the only modern usage is in the phrase “sleep tight.”
As a former child myself, I cannot fail to note the double-edged quality of “sleep tight and don’t let the bedbugs bite” as a bedtime farewell. No one I’ve ever met sleeps soundly after having been reminded of bedbugs. I submit that the phrase is, in fact, probably the diabolical invention of a child, and (judging by my personal experience), most likely an older sister.