Whoa! sfa; that there post is probably the most valuable, and comprehensive collection of information on our rarified hobby I ever saw!
If I'd have come across something like that when I was first dipping my toe into this hobby, I wouldn't have spent the long months reading and searching and searching and reading across multiple fora.

Me personally. I've enjoyed my digging and research into all the myriad terms and abbreviations, and I feel it has given me a greater understanding, rather than just being spoon-fed the answers to specific questions.

To the OP, good luck in your research; I'm sure you'll find it a rewarding experience. And if all else fails, give Google a try. You don't need the rep fora to find out what ETA means.