A non-fungible token (NFT) is the digital representation of the asset. Every NFT, like every cryptocurrency coin, has a unique identifier that anyone can use to track its ownership history on a public blockchain.
We can describe an NFT as a cryptographic token that defines an asset uniquely. It can represent both a digital asset such as an image, but it can also track real-world assets, such as a house or car, or a song, for example.
As you can uniquely define assets, this means you can also prove ownership over said assets, and moreover, prove their authenticity.
Basically, any type of media can be minted or tokenized and turned into an NFT: art, trading cards, memes, gifs, video clips, audio clips, tweets, — anything.
Once tokenized, these assets can be bought, sold and traded using cryptocurrency.