I've always used deep-seated but am doubting myself now.
describes redundancies like "PIN number."
Is the term specific to when this occurs with an acronym? I've heard of pleonasms which I think refers to the use of redundant words in general (e.g.
close proximity) and not necessarily an acronym followed by a redundant word.
Which reminds me that I still don't quite get the difference between pleonasms and tautologies.