Stones of granite wrote:In its non-medical uses, critical is used to denote something on the point of change, whereas stable means that it is unlikely to change. If that were mapped on to medicine it would translate that someone is close to dying (critical), but not in danger of dying (stable).
No, it doesn't.
Critical means "on the point of crisis" not "change" not all change is crisis, and not all crisis is change, These are different things, in the medical field or otherwise.
It's perfectly possible to be close to death (critical), but unchanging (stable); it's also perfectly possible to be ever-changing (unstable) but not close to death (critical).
You may dislike it, but it's nothing to do with acceptable use, so muich as the very meaning of the words - medical or otherwise.