Philly's all-purpose word that can mean basically anything: a thing, a place, a person, or an event. It works like 'thing' or 'thingy', and you figure out what it means from context.
Grab that jawn off the counter for me, and let's head to the jawn on South Street.
Yinz is how folks in Pittsburgh and Western Pennsylvania say "you all" when talking to more than one person. It works just like "y'all" does in the South.
Are yinz coming to the Steelers game on Sunday or what?