What is Nationwide?
1.
Large insurance company, based in Columbus, OH.
"Nationwide is on your side"
See
2.
A person who is uber-fanatical about another person, place or thing
"That guy I met on Friday never called. I guess he just wasn't nationwide on me enough."
"I can see your boss is real nationwide; he didn't even thank you when you came in to work on your day off."