Authenticity means being genuine and true rather than fake or copied. An authentic painting by Leonardo da Vinci is one he actually created, not a clever reproduction. An authentic baseball card from 1952 is the real thing from that year, not a modern reprint.

When people talk about authenticity in how someone acts, they mean that person is being real and honest about who they are. If your friend acts completely different around different groups of people, changing their personality like a chameleon, you might wonder about their authenticity. But if someone stays true to their values and personality whether they're at school, at home, or with friends, they're showing authenticity.

Museums work hard to verify the authenticity of artifacts. Before spending millions on an ancient Roman statue, they need to know it's authentic and not a fake made last year. Historians use scientific tests, compare it to similar objects, and study its history to determine authenticity.

Something authentic is the real deal, not an imitation or pretense. That Roman coin you found while metal detecting? If it's authentic, it was actually struck in Rome two thousand years ago. If not, someone made it recently to look old.