It's also a term in the social sciences that has about 150 years of prior art; or perhaps 2500 years, depending on how you look at it.

elvismercury

My attempt would be something like: btc is a system which instantiates the shared commitment of a group of people to a distributed ledger with dynamics allowing only 21m coins to be created and transmitted under such-and-such circumstances.

Don't use the word "commitment". Commitment is a thing in cryptography with a hard definition that means something else

bitcoin

What's really scarce in btc?

> My attempt would be something like: btc is a system which instantiates the shared commitment of a group of people to a distributed ledger with dynamics allowing only 21m coins to be created and transmitted under such-and-such circumstances.

Don't use the word "commitment". Commitment is a thing in cryptography with a hard definition that means something else