[rewboss]

A more general word is "pleonasm", which many people think means the same as "tautology".

But although every tautology is also a pleonasm, not every pleonasm is a tautology. Any word that it unnecessary is a pleonasm, as here:

This is the man that I saw.

The sentence would mean exactly the same without the underlined word, so it is pleonastic in this sentence. However, it is not a tautology.