"Wax" is old-school hobby slang for sealed packs and boxes of cards. The term goes back decades to when card packs were literally sealed with wax paper wrappers. Even though modern packs use foil or plastic, the term stuck — and it's used constantly.
When someone says "I just picked up some wax," they mean they bought sealed product. "Ripping wax" means opening packs. It's one of those insider terms that immediately tells other collectors you know your way around The Hobby.
Vintage wax — original sealed packs from the '50s, '60s, '70s, and '80s — is a collectible category all its own, with sealed packs from certain years commanding thousands of dollars.