It seems to mean whatever a person needs it to in any conversation.

And yes, in Star Trek, it mostly just seems to mean that food, clothes, and small clonable objects have very little value if you live where those machines are common.

But, of course, that’s not what people think when we talk about a “post-scarcity utopia”. And they don’t think about how people have homes and property and fuel and ships, or how everything bigger than a wrench is allocated by a mega government that seems to have ultimate control over all resource allocation.

We just have to assume “everything is good somehow, and everyone is fine and docile in luxury space communism.” Because they say that.

It’s all very weird, and easy to see why it was all intentionally left unexplained. It would have been a disaster to even try.