that's one of the characteristics of transaction which is it has 3 states, it is either completed, either pending or either failed, besides these, it can't be reverted.
There is no "failed" transaction. There are unconfirmed transactions and confirmed transactions, a transaction can't exist in a failed state since it doesn't exist in either the blockchain or mempool.
I was talking about that transaction that failed due to some problem, whatever wallet we are using. I mostly use meta mask for some small transactions, and I sometimes face failed transactions, and confirmed transaction notifications. Well, I got your main point here, that there are two names for a transaction, confirm and unconfirm.
And failed transaction also comes under the category of uncofirm but to make things more clear I think we can say failed transaction. And I read about these three states of a transaction in DB studies.

As in the pic above, you can see there are confirmed transactions and failed transaction, and when transaction is not completed, its in pending state, so after that, it will either completed/confirmed or failed. That's what I was trying to say.