In English-speaking Canada the term “washroom” is much more common than “restroom,” so it’s not an archaic Americanism, it’s a current Canadianism.
In Canadian French, as in France, they use the entirely unambiguous “toilette,” both for the room as a whole and for the specific piece of plumbing. In French, the word just doesn’t seem to have the squeamish overtones that it does in English.
Of course, even in English, as recently as the early 20th century “to do one’s toilet,” described the entire morning or evening washup, tooth brush and shave ritual.