First Known Case Of Bitcoin Block Chain Reference

Hello Steemit friends.
I hope you are having a great week.

A few weeks ago I was wandering who called it block chain(in terms of bitcoin) first. I reviewed a lot of sources(many which I had read before), and confirmed though Satoshi Nakamoto used both block and chain in his white paper, he does not directly refer to the database as "block chain". I asked our friends at bitcointalk.org, and they led me to an email from Hal Finney to Satoshi Nakamoto in which Hal Finney called it "block chain". The email dates back to 2008, and seems to be a follow up question to Satoshi, thus it may be possible Satoshi had referred to it as block chain in an original email.

I am still interested in knowing where and when "block chain"(in terms of bitcoin) first began to gain mass use. I will continue to do additional research, and I will share when I come across anything interesting.

Here is the link to the email:
https://satoshi.nakamotoinstitute.org/emails/cryptography/6/

Here is the link to my bitcointalk thread:
https://bitcointalk.org/index.php?topic=5022572.msg45393521#msg45393521

Bitcoin white paper:
https://bitcoin.org/bitcoin.pdf

https://pixabay.com/en/photos/bitcoin/

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