It is quite rare that he does not know what a casino is, since it is not necessary to have played in one to get an idea. By watching a movie in which a casino appears, for example, you get an idea. But I guess he hasn't seen one.
OP, there is no better way to get familiar with what a casino is than to gamble in one, but I don't generally recommend it because the math is against you. If at some point you want to try it, be aware of that. There are people who play casino games for entertainment but be aware that although in some cases you may leave the casino with more money, the long term tendency is inevitably to lose money.
With your explanation, I believe you understand this casino of a thing very well. I have read through this topic and know that the OP would have gained a lot of knowledge through it based on what I have read from posters.
The entertainment aspect attracted me so much, there are many reasons and ways we play casinos, but what we do is one, which is gambling. I was not a player until I joined BTT because it is obvious that it is everywhere in the gambling and discussion section, and I need the experience.
My playing is with little amounts and I do that mainly to replace watching movies and all that. A kind of another hobby if I must say, yet I must try not to get addicted.