shibboleth

Meanings

1. A particular pronunciation or custom that is regarded as distinguishing members of a group from non-members, especially when used as a test.
2. A common or longstanding belief, custom, or catchphrase associated with a particular group, especially one with little current meaning or truth.

Etymology

Learned borrowing from Biblical Hebrew שִׁבֹּלֶת /שיבולת (šibbṓleṯ, “ear [of wheat] or stream, torrent”). Doublet of sebboleth and Middle English sebolech, both from Late Latin sebboleth in the Vulgate.