NFT stands for “Non-Fungible Token”.
In economics, a fungible (replaceable) asset is something whose value can be exchanged, such as money.
In the case of money, you can exchange a €10 bill for ten €1 coins, and the value remains the same.
However, if something is not replaceable because it is unique, it is “non-fungible.”
Many works of art, such as paintings, are unique. You can take a photo of the painting or buy a copy, but there will always be only the one original. In the digital world, these unique assets are called NFTs.
They can be bought and sold like any other object, but they are not tangible.
However, since digital files can be duplicated endlessly quite easily, there are digital tokens (certificates) that function as ownership certificates for virtual assets. NFTs thus remain unique and forgery-proof.