Shibboleth

Linguistics, in-group vs out-group

A shibboleth is a word or a phrase that distinguishes one group of people from another.

Wikipedia has many examples (some rather funny): 

In many professions, one may have shibboleths as well, to distinguish those who are more experienced or knowledgeable from those who are not. These may not be used in a password-like manner, rather in a manner like this: "If they use certain words or concepts correctly, it's safe to assume they aren't new to this field".

Learn more:

See more concepts like this

There are many more concepts in my "Mind Expander" tool (it's free)

Check it out