What is the Difference Between a City and a Town?

A man once asked me what is the difference between a city and a town?  A city is bigger I told him.

He then asked me what is the difference between a boat and a ship? A ship is bigger I told him.

What is the difference between a hill and a mountain? A mountain is bigger I told him.

Yes, he said, that’s right, and we left it at that.