In one of my crazy experimentation repos I played with just dropping the confusing "auth" portion, leaving "orization" and "entication". I don't know that those exact terms are a winner, though they did work quite effectively for me, but I think dropping the "auth" bit has some promise in the general sense. Leaving the redundant and confusing part at the beginning and lowering the disambiguation down to one letter seems like the wrong direction, no matter what the one letter is.

The ambiguity of just "auth" is useful when describing it at a higher level.

I can say "auth service" and it's well understood, even to the user, that service identifies them and determines their permissions.

Yep, "authn" is good because it sounds like the first two syllables of "auth-en-ti-ca-tion".

I now agree with you that "autho" would have been better for the same reason. Although "authz" sounds cooler :)

good ol' auth'n 'n' autho'