I was wondering about the origin of using the terms "number one" and "number two" for going to the bathroom (for those unaware, number one is urinating, number two is defecating, at least in the US). I have used it several times myself without actually thinking about it and heard plenty of others use it as well.

A quick Google search showed some interesting yet conflicting results. This site mentions an old school room signal that children would use to ask to go to the restroom (holding up 1 or 2 fingers). But then a post further down claims that is just an urban legend and explains why it is unlikely to be the origin.

I used Google Ngram for "to go number one" and "to go number 2" and it looks like a huge spike started in the mid-to-late 70s. (For jokes I checked "to go number three" and " to go number four" and got no results, I know I just saved a few of you some time!!!).

So, where did the expression originate?

  • I can attest that the convention existed in the 1950s. I suspect that there may be some truth to the story about holding up fingers in a classroom, but it likely goes back to when #2 would imply the need to access the outhouse, while #1 could be accomplished utilizing the side of the firewood shed.
    – Hot Licks
    Commented Apr 13, 2016 at 2:25
  • (The claim in that link that outdoor plumbing had been eliminated 60 years prior to 1902 is pure bullshit, by the way. There were plenty of rural schools with outhouses of one sort or another up until probably 1955.)
    – Hot Licks
    Commented Apr 13, 2016 at 2:57
  • Yea I wasn't too sure about a lot that was in that link... sadly it was still one of the more informative I could find though. Commented Apr 13, 2016 at 3:18
  • 1
    @HotLicks My primary school in rural Sussex still had outside toilets in the mid-1970s. That wasn't exceptional.
    – Andrew Leach
    Commented Oct 14, 2016 at 20:19
  • 1

2 Answers 2


I've deleted my other answer because A Dictionary of Slang and Unconventional English says "number one" and "number two" are from the late 1800s, citing to Joseph Manchon's 1923 Le slang: lexique de l'anglais familier et vulgaire

Also, the 1902 Slang and Its Analogues Past and Present vol. V.-N to Razzle-dazzle has:

NUMBER ONE: ...2. (nursery).- Urination; also a chamber pot

NUMBER TWO: ...2. (nursery).- Evacuation.

  • "Le slang" in 1923! Wonder what the Acaémie Française had to say about that.
    – BoldBen
    Commented Oct 17, 2016 at 13:58

Well, I don't know about people, or little kids... but with dogs, "number 1" is usually the one that happens first. Gotta wait a few minutes for them to do "number 2".

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