When was it first used and in what context?

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    Tom Corbett, Space Cadet Jul 2, 2013 at 22:09
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    @John: Exactly my first thought! Well, not specifically Tom Corbett, but it certainly looks to me like the kind of "future slang" you got in sci-fi from people like Robert Heinlein and Isaac Asimov many decades ago. Apparently we are now actually in that future, but it already sounds horribly "dated" to me. Jul 2, 2013 at 22:16
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    The future is always disappointing when it arrives. Jul 2, 2013 at 22:23
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    @JohnLawler “The future is already here — it’s just not very evenly distributed.” ——William Gibson
    – tchrist
    Jul 2, 2013 at 22:32
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    Welcome Katelyn! What does your research show? Please provide it in your question so the community can benefit from it and not repeat what you've already done. :-) Jul 2, 2013 at 22:38

7 Answers 7


The OED says the phrase "cool your jets", meaning to calm down or become less agitated, is originally US and the first quoted in a newspaper:

1973 Daily Tribune (Wisconsin Rapids) 29 Jan. 1/1 If you want to cool your jets, just step outside, where it will be about 10 degrees under cloudy skies.

That use is to literally cool yourself down. The first with the usual meaning is a bit later the same year:

1973 Independent Rec. (Helena, Montana) 21 Oct. 4/3 Nixon may be able to stifle Congress but he better cool his jets if he thinks he can mess with the rest of the world.

  • Most certainly the Daily Tribune reference was to the slang term and was used in a sort of reverse metaphorical sense.
    – Hot Licks
    Jan 23, 2015 at 18:20
  • There was a flight school run out of the Helena HS that had very close ties to Boeing. I'd bet that searching the Boeing company newspaper/newsletter from 1950-1970 would pay off.
    – Grenoble
    May 27, 2020 at 4:20

The phrase appeared in works by E. E. Smith. I can't do a citation just now - need to get out the books. But that would put in not later than the 1960s, and possibly as early as the 1920s. My best guess is the 1940s or 1950s.

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    I hope that you'll find time to nail down the pre-1970s instance of "cooling [one's] jets" from E. E. Smith. When you post it, I will gladly upvote this answer.
    – Sven Yargs
    Mar 9, 2015 at 2:35

Like the OED (which Hugo cites in his answer), J. E. Lighter, Random House Dictionary of American Slang, volume 1 (1994) gives a first occurrence date of 1973 for "cool [one's] jets":

cool (one's) jets to take it easy; become less less agitated or excited.

[Examples:] 1973 Eble Campus Slang (Nov.) 1: Cool your jets—settle down and relax: Cool your jets or the cops will still think you're the guilty one. 1978 UTSQ Get off my case, cool your jets, take a hike. 1980–89 Cheshire Home Boy 310: Martinez ... bops him one ... Cruise cools his jets. 1989 Dream Street (NBC-TV): Cool your jets, man. He's my brother.

But a Google Books search finds an instance of "cool your jets" from 1970. From William Walter Scott, Hurt, Baby, Hurt (Ann Arbor, Michigan: New Ghetto Press, 1970): [combined snippets]:

If you're getting bored like hell, the feeling's mutual, but just cool your jets and wait for a while. I've sorta got to talk about the conflict between me and my old man.

Like during this time there were lots of undercurrents that forced me to put my foot down and say the hell with what other people say. I've got to start thinking for myself. That was the gist of it.

Hathi Trust confirms the book's publication date and notes that "cool your jets" appears on page 53 of Hurt, Baby, Hurt, but it declines to reproduce its content, owing to copyright restrictions.


I am unable to provide a proper citation as I seem no longer to have a copy of the book available. However I believe E. E. "Doc" Smith used it in "Gray Lensman" (serial published in 1939-40, book in 1951). About the second or third chapter Kinnison attended some sort of soiree where he was treated like a rock star and swarmed by young women. "Cool you jets" was used in the course of the conversational repartee. As I recall there were many other future slang references to jets - clogging, not firing on all jets, and the like. Apologies for lack of citation.

  • I ran a search for jets on a free, searchable online copy of Gray Lensman (which was originally serialized in 1939–1940 in Astounding Science-Fiction), and found three idiomatic phrases involving jets: "clog [one's] jets" (six occurrences in the novel), "burn out [one's] jets" (two occurrences), and "baffle [one's] jets (one occurrence). I think you may have misremembered "clog [one's] jets"—meaning "cramp one's style" or "make trouble for one"—as "cool [one's] jets." The latter does not appear in the novel.
    – Sven Yargs
    Apr 10, 2016 at 18:11

The n-gram is instructive https://books.google.com/ngrams/graph?content=cool+your+jets&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Ccool%20your%20jets%3B%2Cc0 Note the origination in the early 40's, almost certainly in pulp SF. In the absence of direct attribution, the suggestions of other answers of Smith or Heinlein seem very likely, although Tom Corbett "Space Cadet" is a few years too late to be the first use. It then seems to have fallen into disuse until the mid-60s.

  • If you shift your Ngram's smoothing to 0 (from 3), you'll see that the claimed matches for the uptick during the early 1940s are entirely from 1942. But if you check the individual matches from the first reported set of dates (1800–1984), you'll find that none are earlier than 1970. To see whether a match might be lurking at a finer level of filtering, I changed the search period to 1940–1980, which yields a separate results link for 1942 alone—but none of the matches for that year are exact matches for "cool your jets." My conclusion: The "matches" Ngram claims from 1942 are illusory.
    – Sven Yargs
    Apr 10, 2016 at 17:50

the term cool your jets came from the P2 Neptune aircraft use after World War II as a sub Hunter it had to radial engines and two outboard jet engines after takeoff they would turn the jet engines off the cool your jets that's where it came from

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    Can you add some sort of reference -- even personal knowledge as a pilot of that era would be helpful.
    – ab2
    Apr 10, 2016 at 14:12

I thought it might be a military term like for pilots or maybe its meaning is it's so cold you can cancel a jet engine heat, like the afterburner on a fighter plane

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    Can you provide a citation? Otherwise, this seems like idle speculation.
    – choster
    Dec 12, 2013 at 15:42
  • For somone who does not understand that queer expression the first thing one wants to know is in what sense "jet" is used, and what area this picture belongs to. Ste is the first to say that " jet" might refer to jet engines or jet fighters. The second thing that interests is what is the meaning in normal language . The year when such a queer saying came up and the TV-series is of minor importance, at least for me.
    – rogermue
    Mar 9, 2015 at 4:08

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