Is it a euphemism or slang? I think it is both. We are naturally averse to talking about bodily functions in polite company. So we employ euphemisms that say what we need to say without coming right out and saying it. Nowhere is this more true than with #1 and #2, or “wee wee” and “poi poi” in my house when I was growing up. I am of course talking about urination and defecation.
There should be no shame in coming right out and saying what you mean in this regard. These are natural things we, and all living creatures, do. In fact, I’m having some problems with the first one, so I’m seeing a doctor who specializes in it, called a urologist. If there’s a medical specialty for it then it ought not be a source of embarrassment to talk about. Still, people are squeamish about this one particularly, so we employ all manner of euphemisms and over time these become slang terms. What interests me is the origins of the terms.
Whether its loo, privy, or head (which is a dual-purpose euphemism that can also mean something very naughty), we are referring to the toilet. But how did these come to represent that. I am an anglophile and very proud of my family’s English heritage, so it won’t surprise you to learn that the origins of “toilet slang” trace back to medieval England, where the process (and necessity) of relieving oneself was referred to as a trip to the “jake” or “jack,” names for public toilets used by everyone.

It was Sir John Harrington, seen at left in this portrait painted by Hieronimo Custodis around 1593, who invented the flushing toilet in the late 16th century, announcing this advance in 1596 with his treatise “A New Discourse of a Stale Subject, called the Metamorphosis of Ajax.”
Of course, “ajax” was a pun for the public toilet, or jack (plural “jacks” which could be read jax). His new invention was initially called an Ajax because of this. The Ajax was a huge leap forward in sanitation technology. His design with a raised cistern holding water that was released and used to “flush away” the waste product left behind led to what we know today as the modern flushing toilet, and his work inspired others, like Alexander Cumming, who got the first patent for a flushing toilet in 1775.
We know there was concern for cleanliness and privacy by some of the other slang terms used for the location of the toilet, such as “loo” which comes from the days of throwing away chamber pot contents and is linked to the French saying guardez l’eau (l’eau pronounced loo) which means “watch out for the water,” and “privy” which comes from the Latin privatus meaning “private.” Referring to the room the toilet is in as a “lavatory” comes from the Latin lavare which means “to wash.”
But it was John Harington’s relationship with royalty that I think is the most likely reason we call a toilet a “john.” He was known as the “saucy godson” of Queen Elizabeth I and is said to have installed his new flushing toilet in her palace and the homes of her wealthy, often noble, courtiers around the turn of the 17th century. Association with his invention and a royal connection led to referring to the device by the name of its inventor.
It is also during the 17th century that another common term for the toilet developed because of its location in the front of ships, or the head of the ship if you will. Thus, going to the toilet to relieve yourself meant going to the head. And by 1861, it was Thomas Crapper, an English plumber and businessman in London, that manufactured a popular line of flush toilets and developed the ballcock mechanism, which is why we say “going to the crapper” or “take a crap” to mean defecating.

But pride of place goes to John Harrington as the inventor of the flush toilet and therefore the ubiquity of naming it after him. Still, we euphemize what we do at or in the john, presumably embarrassed by our own bodily functions. I think some of the common euphemism are examples of onomatopoeia, the formation of a word from a sound associated with what is named, such as “tinkle” for urination or “taking a dump” for defecation. One of my favorites in regard to the latter is “dropping the kids off at the pool.”
And there you have it. Now let’s have a little fun. Send me what you call “using the toilet” or the room the toilet is in by clicking here.
