I think most Americans just refer to it as the “bathroom” and most bathrooms do have bathing facilities in them. If there is no bath or shower, this room is referred to as a “half bath.”
Since Jack Parr left the Tonight Show because they wouldn’t let him use the words “water closet” in a joke in 1960, I have a little porcelain sign on my bathroom door that says “W.C.”
I kid you not.
… so clearly the other part of the job should be done by the word “arsenal”.
In my travels through Europe (including France), I’ve certainly seen and heard “pissoir” many times, but never “urinoir.” Perhaps it’s a Quebecois word?
Regardless, I’ll remember that for when I’m next in Quebec. There are some excellent beers brewed there, which usually mean … well, you know. And I’d like to make sure that I get directed to the correct room. 
Here a bathroom with no bath is referred to as a 1/2 bath. Further, a bathroom with a small shower stall but no bath is a 3/4 bath. Thus, the recent real estate ad which claimed a house had 2.25 baths, which took me a while to decipher.
I vote for lavatory. Because defecatorium and excretorium both seem to indicate that the guys, at least are in the back yard peeing on the electric fence. As if that room is only used for “number two.”
But whatever else we may do in there, we all wash our hands afterwards. Don’t we now? [Glares around the room with the eye of a nun daring schoolboys to react to her order to decline (the verb) “to Come”.]
Huh, how about that. I still think “pissoir” sounds vulgar, in the same way that “pisser” is more vulgar than “uriner”. I’ll try to remember not to let this word shock me too much if I see it in another French-speaking country.
But yes, in Quebec the common term for a urinal is “urinoir” and I thought it was also true internationally.
I’ve always like “lavatory.” It sounds like where you would spark life into Frankenstein’s monster.
I vote for shittoon.
Pure. Genius.
Tincan715 is only partly correct. The head being in the bow of a sailing ship is practical, because on a sailing ship the wind comes roughly from behind. (It may be to one side, but more or less from behind.) Naturally, the ship sails slower than the wind, so the wind blows from the stern towards the bow. Having the head in the bow meant any smells were blown forward, not back through the ship.
Are there any former Boy Scouts who are not familiar with the term “kybo”?
raises hand
Grew up in Arkansas. Not familiar with word “kybo”.
It was “the wayside” at Medomak Camp for Boys in Washington, Maine, at least back in the 1950s and 60s.
I learned kybo as an acronym for Keep Your Body Orderly. (I see the wiki link claims Keep Your Bowels Open :dubious:)
In that sense I associated it with the camp building with showers and sinks. Toilet only bathrooms were not referred to as kybos. YMMV
Or we could just choke back our squeamishness and call it what it is: The toilet or the toilet room.
And if we must choose between restroom and washroom, I think washroom is a little closer to the reality. At least, I HOPE you all wash in the restroom! If not, don’t ever shake my hand!
You miss the point. Toilet is a euphemism, or at least it started out that way.
Yes, “toilet” was just the lady getting dressed and made up in the morning. I’m reading Theodore Dreiser’s An American Tragedy right now, published in 1925, and it has a young man in his early 20s coming down to breakfast “after finishing his toilet,” meaning after he’d shaved and dressed.
Was a scout. Never heard the term “kybo”. Wiki section is undocumented.