A plane extends infinitely in two dimensions. It has no thickness.The plane has two dimensions: <u>length and width</u><u>.</u> But since the plane extends infinitely,the length and width cannot be measured.
Lets take an example of a flat sheet of metal. Imagine a flat sheet of metal. Now make it infinitely large in both directions. This means that no matter how far you go, you never reach its edges. Now imagine that it is so thin that it actually has no thickness at all. In spite of this, it remains completely rigid and flat. This is the 'plane' in geometry.
