Mark is chatting with his classmate Ming in the common room of their dorm.

    Ming: Hi, Mark. Can I ask you a kind of embarrassing question?

    Mark: Sure!

    Ming: When I have to go to the toilet, what can I say?

    Mark: You mean, in a sort of formal situation?

    Ming: Yes.

    Mark: Well, what you just said--"I need to go to the toilet"--is just fine.

    Ming: But I heard some people say that's too direct.

    Mark: It might be. So some people say, "I need to use the restroom" or "go to the bathroom."

    Ming: But I don't want to take a bath!

    Mark: I know. But in many homes, the toilet is located in the same room where people take a bath, so...

    Ming: I see.

    Mark: Another common expression is "to use the WC."

    Ming: I've heard that! But I don't know what it means.

    Mark: Toilets have been called "water closets" for many years. I think at one time they were in their own, small room, like a closet.

    Ming: Now I get it!

    Mark: This might also have given rise to a common slang term: "to go to the loo."

    Ming: I've heard that, too, but I don't know what it refers to.

    Mark: There are several guesses about the meaning. One is that British soldiers in France heard the term "lieux d'aisances," or "place of ease," and started calling it "the loo."

    Ming: That makes sense.

    Mark: Another explanation is more fun, though. They say it might be short for "Waterloo," the place where Napoleon was defeated.

    Ming: Water closet. Water loo. I get it. Funny!

    Mark: I think so, too.

    Ming: Are there other slang words for going to the toilet?

    Mark: Tons! One is to say "go to the potty" or "take a potty break."

    Ming: That sounds like baby talk.

    Mark: It is! And sometimes moms and dads would ask the young child, "Do you have to go Number One or Number Two?"

    Ming: Meaning?

    Mark: Uh, let me just say, boys usually go Number One standing up. Everyone sits for Number Two.

    Ming: Got it!

    Mark: Another sort of baby talk is to say "I have to go to the little boys' room" or "the little girls' room."

    Ming: Wow! So many expressions!

    Mark: There are lots more! If men are together, they might say, "I have to go see a man about a horse."

    Ming: Why?

    Mark: No one knows! Another is "to spend a penny."

    Ming: Is that because some toilets had to be paid for?

    Mark: Probably. Women might say, "I have to go powder my nose."

    Ming: Because they fix their make-up in front of the mirrors.

    Mark: Yes. And anyone can say, "Nature calls," or "I need to answer the call of nature."

    Ming: That's a good one! I think I'll use that.

    Mark: Good! Now, if you'll excuse me, I have to go wash my hands.

    Ming: Oh! I think I know what you mean!