What is the difference between "cracker" and "cookie"?

I did not know, neither did I ever think about it.

Then yesterday at pickup----

Peter told me "I want a cookie, mama." I said "OK, mommy will give you some in the car." -----I remembered that there is some "Graham cracker" in the car. But the bad part was that I did not realize that "cracker is not cookie."

So, it was horrible when he saw what was in my hand. Obviously, our "terrible two" felt very offended by his own mother and began to cry, or scream.

The worse part was, stupid me still did not realize what was the problem until I said, "why? you said you want a cookie, and this is the only thing mommy have, Graham c---" Right there, at the tip of my tongue, I finally realized that it was a cracker, not cookie. That means that our little guy did have the right to be fussy. Fortunately, it did not take long for Peter to calm down and accepted what I had. But for me, the big question became "really, what is the difference between cracker or cookie?" "Maybe one has butter while the other one doesn't?" I thought.

Then today I looked it up online and here's what I found.

cracker: A thin crisp wafer or biscuit, usually made of unsweetened dough.
cookie: A small, usually flat and crisp cake made from sweetened dough.

Well, now it is clear why cookie is better than cracker. "sweet" is the key, huh? I am learning, constantly.