Battlefield 6 Wiki
Battlefield chat is full of shorthand, and some of it comes from older games in the series rather than from Battlefield 6 itself. The Onlyfarms wiki collects the words that come up in voice comms and in the chat, from gadget names to team slang.
The AA (Anti-Air) entry is a good place to start. In Battlefield 6 the Engineer class has an Air-Defense Launcher gadget that locks on and fires a tracking missile at jets and helicopters, and stationary anti-air guns are another way to deal with aircraft. Airburst refers to ammunition that detonates above a target, and one example from the series is the XM25 in the Support kit of Battlefield 4. Angels comes with its Battlefield 2042 background: Angel is a specialist there who can revive teammates and call in loadout drops. The list also has Armor Boi, a slang entry.
If you want a hand in the game itself, Battlefield 6 services from Onlyfarms are one option, and the Battlefield 6 guides go further than a glossary entry can. Gaming words that exist outside Battlefield are in the general gaming wiki.