Term: passphrase

A passphrase (or pass phrase) is simply a password constructed of multiple words. Typically, though not always, the words in a passphrase are separated by spaces, as one would normally type.

The advantage of a passphrase is that it’s significantly easier to remember than complex passwords, and therefore can be significantly longer. Much longer passwords are generally considered more secure, even when they’re composed of common dictionary words. Even then, a simple alteration – perhaps replacing all of the spaces with periods, or all of the letter Os with number 0s, which can be easily remembered – can further obfuscate and make even dictionary-based attacks a practical impossibility.

The limiting factor is typically the system on which the password is to be used. Many do not accept spaces or allow for a sufficiently long password for a pass phrase to be used effectively.

One example of a passphrase is “correct horse battery staple“, made popular by the webcomic XKCD. It also shows that the phrase need not even make sense, as long as it’s memorable.