ATHENS — Here in the land that gave us the word “cosmopolitan,” the use of the term by a top aide to President Donald Trump was met with some bewilderment.

At a news conference Wednesday, senior White House adviser Stephen Miller accused a CNN reporter of “cosmopolitan bias” after the journalist questioned him about Trump’s support for a proposal to limit legal immigration.

“I didn’t know that was an insult,” said my mother, a retired suburban school secretary who was born in a poor village in the mountains of southern Greece but moved to the North Side of Chicago when she was 12, learned English quickly, became a U.S. citizen and now spends most of the summer near her homeland’s blue sea.

OPINION

At the risk of sounding like the immigrant dad from “My Big Fat Greek Wedding,” allow me to present a brief etymology lesson.

The English word “cosmopolitan,” like so much of the English language, comes from Greek. It’s an amalgam of “cosmos,” which refers to the world or universe, and “politis,” which means citizen.

The Greek word cosmopolitis has never been an insult, not in ancient Greece nor among today’s descendants of Homer and Aristotle, says my college roommate Costas.

Then again, you might call Costas a cosmopolitan.

He spent a few years in Boston as a small child and returned to the U.S. many years later, getting his doctoral degree from the University of Missouri in the 1990s. Costas lives in Athens again now, despite the country’s long-running economic crisis, but his frequent business travels around the world include visits to the U.S. to work with American colleagues.

I’d venture to guess very few Greeks — perhaps just members of the neo-fascist Golden Dawn political party — would see cosmopolitis as an insult.

As I sat waiting to fly home Thursday from the international airport of Athens, I tried this theory on the waiter who served my last iced frappé of vacation in my ancestral homeland.

“What would you think if I told you that you’re a ‘cosmopolitis,’” I asked the young man in Greek. “Good or bad?”

“I suppose that would be a good thing,” he said. “It means you’re a guy who travels around the world a lot.”

That Miller wielded the word as an epithet shows starkly the us-versus-them worldview that prevails in the Trump administration.

The implication is that the U.S. is so besieged by enemies that those of us who would see kinship with the rest of the world  — rather than viewing outsiders with pure suspicion — are somehow naïve at best, and maybe even complicit in our national destruction.

If you’re a cosmopolitan, in other words, you’re un-American. Or at least acting against the interests of our country.

The ancient Greeks, like modern Americans, had their foes. Those Greeks also came up with the word “barbarian,” as an insult against those who could not speak their language.

In Athens’ spectacular Acropolis Museum, which my family toured this week with Costas’ wife and daughter, we saw remnants of these struggles between warring peoples and cultures. Some of the marble artifacts in the Acropolis Museum still show the effects of the destruction that the Persians wrought when they sacked the Athenians’ citadel, before the Greeks finally defeated them to preserve their freedom.

But the Greeks did not become the dominant people of the ancient world, spreading their rich culture across the known world, by shutting themselves off from others.

“The gods visit us disguised as strangers,” Homer wrote in “The Odyssey.”

And the U.S. has become the modern world’s beacon by taking the best from those who wanted to offer their talents and efforts.

When you hear someone use “cosmopolitan” as an insult, another word with Greek roots should come to mind.

Xenophobia. The fear of foreigners.