I think we need a new word or phrase. Identity carries a lot of meaning and is as confusing as account that isn’t actually an account of anything. Technically I’d call it a certificate. But in practice we call analogous certificates all kinds of things, like a card or a licence or a number (real clever that). Those are mostly issued by some authority and self-issued on nostr (and btc), but in essence hold a private key for some predetermined purpose. I’d like to convey that, if at all possible.