What does prototype drug mean?

I looked up the definition but I'm not quite sure I understand.

To me, I feel that it means an example of a very common drug or one of the top drugs of that class?

Can anyone help give me a better definition? I'm taking pharmacology online. I started yesterday. It's 6 weeks long, I'm already stressing out. I began a week early reading.

Thanks :)

[Central BSN, RN]

It's the prototype of a medication. It's the blue print and first form of a drug that is used to make other and alternate forms of the drug.