Is there an Investment-related wiki that is available?

Hey there!

For a start, perhaps you can check out Investopedia (https://www.investopedia.com/) which gives a very concise explaination of the concepts that you just mentioned. On top of explainations, Investopedia also provides video examples for people who are more visually inclined.

Some other plus points of Investopedia is that it covers many aspects of investing, beyond the 2 concepts that you just brought up. For instance, it also teaches you the basics and foundations of investing as well as introduce you to financial assets such as deriatives.

Hope you find this to be helpful!

Here you go: https://www.investopedia.com/