What does antediluvian mean?
This word means "before the flood" or (in a figurative way) something from a very, very long time ago. It can also mean very old-fashioned (as in "he had a very antediluvian attitude towards women").
For me the best way to remember it is this. First, you should be able to remember that "ante" means "before." If you speak Spanish, you know that "antes" means "before." And the "A" in AM means "ante" or "before. Second, I think that "diluvian" sounds like "deluge" (at least the "diluv" part does). Since "deluge" means flood, that's how I used to remember this word.