An ellipse might be called a flattened circle. If you take a tin can and press the two sides of the open end of it inwards, it will form an ellipse. The dictionary says that an ellipse is a conic which does not extend to infinity and whose intersections with the line of infinity are imaginary. Now that is a very lucid explanation! I hope you understand it, it is so simple, but it is just like a dictionary to say such terrible things about a harmless ellipse. To tell the truth, I thought I knew all about an ellipse until I read this explanation; but never mind, we know what it looks like and if we do not know what it is, we do know that there are a lot of things besides ellipses that do not extend to infinity, and we also know that an ellipse is a practical form for a council fire in spite of the hard names the dictionary calls it. This oval is really shaped like the body of a theatre and it gives the audience a chance to see what is doing on the stage, and the people on the stage a chance to see and address the audience.