Unique means being the only one of its kind, completely unlike anything else. When something is unique, no duplicate or copy exists anywhere. Your fingerprints are unique: no other person in the world has fingerprints exactly like yours, not even an identical twin.

A unique artifact might be the only surviving example from an ancient civilization. A unique talent combines skills in a way nobody else has quite matched. When scientists discover a unique species, they may have found a creature that does not fit into any known category.

People sometimes use unique more loosely to mean “very unusual” or “distinctive,” as in “That restaurant has a unique style.” Some writers and speakers try to reserve the word for things that are truly one of a kind, using words like “unusual,” “rare,” or “distinctive” when something is merely uncommon rather than singular.

When you call something unique, you're saying there's nothing else quite like it in the entire world.