I was doing some maths with a small girl this evening who always has erasers in the shapes of animals and things. She got out a dolphin one to rub out the top of a fraction.

“Do erasers get names?” I asked.

“No this one hasn’t got a name, it’s just a dolphin one. I gave a dolphin one to my friend though, and now she uses it for her exam mascot and she’s given it a name. But she doesn’t use it to rub out.”

So you can see that if you use an eraser it can’t have a name, and if it’s got a name you can’t use it.