'Non-fungible tokens': the etymology behind this new digital swag

Sadly, it has nothing to do with fungus

When is an album not an album? Why, when it's a non-fungible token", a new form of digital swag, related to cryptocurrency, being sold by artists and musicians such as Kings of Leon and Grimes. They're called NFTs for short, but why?

Perhaps disappointingly, fungible" does not mean capable of being turned into fungi". Rather, the Latin verb fungi means to discharge some office or perform some task, and so fungibilis means useful", and English fungible" specifically describes useful things that are interchangeable. If I order five spoons of a certain design, it doesn't matter exactly which five of those spoons you send me.