[Syntax]

Hi. I have a few questions written down for you, dear members of this wonderful community. Although, a buddy that I've just met explained me a few things, I've only partially understood what he said, but I can assure that each and every beginner had problems with this.

1. What is a stock?
2. What is a string?


Please give me an in-depth explanation (including examples) for each of them. You will be given a reputation point, should you make me understand.