"Notepad" vs. "notebook" — what's the difference?

Can you please tell me the difference between a notepad and a notebook (as in paper, not electronic ones)?

To me, they are the same but I guess there must be some difference.

Solution 1:

In general, notebooks are more firmly bound (often with a metal spiral) and of a larger size. The binding often exists on the long vertical edge of the page.

A notepad, on the other hand, tends to be smaller and designed so that the pages can easily be removed. The binding is frequently at the top of the page.

That said, you can have little notebooks and large notepads, and they can all be bound in various ways. The most consistent difference in my mind is that notebooks are sturdier and more likely to stay in one piece, while notepads are flimsier and more likely to have pages removed.