Is there a significance to the word "salt" for a password salt?
The only meaning is that you are adding something to your password before you hash it, similarly to adding salt to your meal :-)
Because before you hash the password, you add a random text to it. So, it looks like as if you add some "salt" to the original "food" ... password :)
http://www.derkeiler.com/Newsgroups/comp.security.misc/2003-05/0154.html
The use of the word "salt" is probably a reference to warfare in ancient times, when people would salt the wells or farmland to make it less hospitable. The Romans are sometimes supposed to have done this to Carthage in 146 BC. In the context of passwords, a "salted" password is harder to crack.
Apparently, there's no strong evidence even for the original "salting" of Carthage (http://en.wikipedia.org/wiki/Salting_the_earth) claim, but an interesting hypothesis nonetheless.
I would guess because it's easy to add "salt" (NaCl or a fixed string). But once you do, the output is irrevocably changed (food, encrypted password).
According to Ken Thompson, one of the first people to use the term in a book, it's related to the term "salting a mine", referring to gold mines. Whether that is "correct" or not who knows? I doubt there's an actual correct answer to this, it's just one of those terms that doesn't really have to have a reason as long as what it means is understood.
Unsalted passwords are too plain. Being simple text, an unsalted password is typically shorter than the side of the hash, thus ensuring that only a subset of hash outputs are possible. This means that hashes of passwords are suceptible to dictionary attacks and/or other cryptographic analysis based on the reduced keyspace.
salting the password with random, or even fixed data, removes or mitigates these attack vectors.
I had thought it related to the verb salt ...
(salt away) informal put by (money) secretly.