A token is the digitized form of an asset. The token therefore has a certain value or a certain function. At the same time, however, real assets such as real estate or music rights can also be tokenized by transferring the associated rights and obligations to the token. This means that the ownership structure is digitally mapped and can therefore be traded. A token can be both fungible (exchangeable) and non-fungible (not exchangeable). Basically, "non-fungible" in this sense only means that it is a unique digital asset that cannot be exchanged one-to-one for another.
The situation is different with bitcoins, for example: Bitcoins can be exchanged at will, as they always have the same value. It is the same with cash: a ten-euro bill has the same value as another ten-euro bill. Non-fungible tokens, on the other hand, can be compared to art objects such as paintings. These have an individual value. If you exchange them for each other, you usually don't get the same value that you pass on.
Source: Stuttgarter Nachrichten, 2021
https://www.stuttgarter-nachrichten.de/inhalt.nft-was-ist-das-mhsd.386bd7ac-2e41-461d-b726-cd5a6f0d2096.html