Can a person really be considered "famous" if they are virtually unknown outside their country?

Sure.

A person can be famous in their own city, even if no one else outside the city has never heard of them. There isn’t a yardstick of “what does famous” mean – there couldn’t be.

It’s all relative.

I’m sure it’s a levels of fame thing. Local celebrity, national celebrity, international celebrity. I’m pretty sure Leonard Nimoy is an interstellar celebrity.

To me, fame can only be measured on a global scale, these celebrity losers with zero fucking talent are & never will be famous.

Depends on the reach and size of the country.

Johnny Carson was known everywhere in the United States, but was virtually unknown in Europe. Yet I would consider him famous.

Even within a country (the U.S., for example), someone may be regarded as famous by some portion of the population just because he or she is a celebrity within some definable context. I often react with the same “Who?” to news about Americans that “everybody” supposedly knows. But if they’re TV personalities or sports figures, chances are I’ve never heard of them. Maybe they’re actually famous, even though they’re nobodies to me; or maybe that’s just not fame at all.

Yes, fame (or infamy) is relative. A person can be (in)famous within his own family, around her own town, or throughout his general region. Each is a microcosm of society at large.

If you’d like a good example, go to Google News and search for “Charles Severance.” I’m guessing that people beyond my area have never heard of him. Within my home city of Alexandria, and throughout greater-DC, everyone knows exactly who he is and what he’s done.

(An aside. If you do look up Charles Severance, can you BELIEVE that this man is age 55? He looks about 25 years older. Murder and lunacy take their toll.)

That’s a nice thought. I totally agree with you on the point @ragingloli
I think fame should be categorized as local or global or something like that. But that’s not in our hands, right?

Yes and why we have qualifiers like ‘legend’ and ‘superstar’ to define the really famous people.

I think it’s generally assumed that the given person is ‘famous’ within the target audience of the reporting media.

The local newspaper is going to have a different definition of fame than Reuters and both will depart from, say, Sports Illustrated.

You can be “famous for…” even within your own family or circle of friends/enemies.