Brainstorming to understand the general software principles of cryptocurrencies

After reading about bitcoin a while back, around 2010, I only acquired an overview knowledge about it.

It is now time to improve that understanding a little more, to be better equipped when trying to assess the status and validity of any of these cryptocurrencies that have emerged since then.

Many articles have been trying to explain bitcoin already of course. Why write another one ? Well, by writing it, I will progress in my own understanding as I will have to be active in this process. We will see how this goes.

For a start, here are few questions we will try to answer:

Where does the word 'currency' come from ?

What are the key elements to understand that are
important building block of cryptocurrencies:
1- "cryptographic hash function"
2- "proof of work"
3- blockchain
4- mining
5- ...probably quite a few more

Of course any suggestions in the comments are welcome. Please keep in mind that we are trying to analyze the core elements of a cryptocurrency.

Intuitively Cryptocurrencies now appear to be a powerful tool. We are simply trying to improve our understanding here to better navigate that new field.

This is a work in progress.