What is the singular form of NOSE?

I was chatting with one of my English teachers the other day...preparing for a class of 1st graders. This teacher is really great, and usually right on top of things. But today...well, i don't really know what was going on. So we were going over the lesson which was teaching body parts to the kids. At the end of the class, before each kid leaves the room, I always ask them a question to see if they understood the day's lesson. For my Wednesday lesson, I was to ask if the kids could touch their eyes, nose, mouth, ears, etc. Well, I guess the kids get really confused when I say things like eyes vs eye...since they don't know the plural versions of things. I was asked not to say the plural of anything (like eyes or ears) when talking to the kids. Well, that isn't too difficult so I quickly agreed. Then the teacher said, "well we have another little problem...what is the singular of nose?" I was like, "umm...nose." And she was like, "Yeah...nose....like hana." and I say again, "nose is the singular of nose." This got her really confused, because she kept saying no that means there are two of them....what would only one be?" I explained that "2 = noses, 1 = nose". She still wasn't getting it, because she was putting up a big argument that I was wrong. I just stood there thinking..."what on earth is this woman on? What could the singular form of nose possibly be other than nose? I mean no or se doesn't quite cut it..." This conversation went on for over 5 minutes before I figured out that she was talking about nostrils when she was referring to the nose....and that when people usually refer to them, they are in the plural...and really, she just wanted to know what the word for 1 nostril was. So there you have it...yet another ridiculous conversation in my world.