shibboleth

1. A word or pronunciation that distinguishes people of one group or class from those of another.
2. A word or phrase identified with a particular group or cause; a catchword.
3. A commonplace saying or idea.
4. A custom or practice that betrays one as an outsider.

Thanks to Dinosaur Comics for teaching me this interesting word.

Thanks also to Questionable Content for introducing me to something that I totally don’t need but now want for the new apartment.