This probably has alot you know, but maybe some you don't.
https://www.leafly.com/news/cannabis-101/glossary-of-cannabis-terms
I would check out some cannabis growing blogs, lots of information on the web... just don't take everything as complete fact, I'm assuming you know this but the internet is full of bad advice... I have a Pappa smurf tattooed on my left cheek to prove it... okay maybe not but back to the subject in the res.
I'll start with that. Res means Reservior. kinda basic but just thought Id throw it in the mix
Bennies are beneficial bacteria... Trichoderma, Mycorrhizae, Bacillus, there are lots of those. They can be used to break down organic matter so it can be digested by your plants... They're needed when your using anything that your plant can't take up directly.
Bennies aren't needed when using chelated nutrients though, which are readily available for your plants.
from my understanding DI is De-Ionized water. its basically distilled (or purified by other means) water that has no charge/has had the Ions removed.
http://www.waterandmorehub.com/deionized-water-vs-distilled-water/