I'm interested in learning the essence and background of this community and the concepts it is built upon. Beyond who founded Ethereum, who is responsible for coining terms such as block-chain? Why did they coin the term that way, and what were their inspirations? I'm looking for bulletnote-style answers more than a discussion.
A block chain is an old cryptographic construct where encryption is done in blocks, with each block encrypting a certain number of bits of the plaintext. To decrease the possibility of some attacks, like frequency analysis, encryption of each block uses some input from the previous block as part of the key for the next block.
While this doesn't have anything to do with a distributed database, it does have to do with the work the miners do. Specifically, each new block uses the previous block as an input, referencing the block it was built on top of. With these references, it is possible to calculate the length of a block chain and, more importantly, the amount of work done on a specific chain.
I don't know where the term "block chain" originally came from, but a small amount of Googling brought me to a reference that is at least as old as 1976. Beyond that, I know that there is no reference to a "block chain" in the original Bitcoin white paper.
The original White Paper is probably responsible for the term's popularity. Although Satoshi never uses the term "blockchain" or "block chain" s/he frequently uses the term "chain" in association with a series of blocks, and often in the same way we use "blockchain" today. For instance, on page 3 Satoshi writes:
"As later blocks are chained after it, the work to change the block would include redoing all the blocks after it."
And on page 7:
"This prevents the sender from preparing a chain of blocks ahead of time by working on it continuously until he is lucky enough to get far enough ahead, then executing the transaction at "that moment.
The bitcoin white paper is probably responsible for our use of the term blockchain in this context today.
As to who first used the term in its modern form as "block chain", the earliest reference I can find is a conversation between Hal Finney & Satoshi on November 9, 2008 where Hal writes:
it is mentioned that if a broadcast transaction does not reach all nodes, it is OK, as it will get into the block chain before long.