Hello, welcome, it’s always nice to see more new people! I saw you mentioned terminology; most of the time people abbreviate items and mechanics. There is a list of VG terminology, but feel free to ask anyone to explain what they’re talking about, I’m sure most people here won’t mind.
There’s a list of all the items in Vainglory here if you’re ever totally lost. I still use it to remind myself, and I think I’ve been playing for almost 2 years. Keep in mind also that when most people are talking about builds, they’re talking about T3 (tier 3) items, so if any two items share the same initials/abbreviation, you might assume it’s the highest tier.
@Ve3nNo0wM’s advice is solid. Learning the items quickly will definitely help ease your way into Vainglory, and will let you feel more “in the loop” here.