A store of value is something that keeps its worth while you are not using it.
Why it sounds harder than it is
It sounds like a vault. It is a question.
The question is: if I put this away and come back in ten years, what will it buy?
Nothing answers that question with certainty, which is why the phrase is always hedged when careful people use it. It describes a job something is being asked to do. It does not say how well anything does the job, and anyone who tells you a particular thing does it perfectly is selling you something.
The formality of the phrase hides how uncertain the idea underneath it is.
A concrete Australian example
The fifty dollar note your grandmother put in a birthday card in 2010 is still a fifty dollar note.
It buys less than it did. Nobody took anything from you and nobody made a mistake. The note held its number, and its number was never the same thing as its worth.
The gap between the number and what the number buys is what the phrase is asking about.
What it is not
- Not a promise. Nothing is guaranteed to hold its worth, including cash sitting in a bank account
- Not the same as a medium of exchange. Something can be easy to spend today and worth less to hold. The two jobs pull in different directions
- Not a ranking. The phrase describes a job, not a league table. Whenever you see it used to argue that one thing beats another, the argument is being smuggled in under a definition
Related
If you have ever found an old note in a coat pocket, you have already run the experiment.