Shibboleth

A shibboleth () was originally a single word which distinguished one group from another.Concise Oxford Dictionary, 8th ed, (Oxford University Press, 1990), 1117.Merriam-Webster Dictionary, shibboleth, accessed online 22 September 2015.Collins English Dictionary, shibboleth, accessed online 22 September 2015.

Rather more widely, it is any custom or tradition that distinguishes one group of people from another. Shibboleths have been used throughout history in many societies as passwords. They are simple ways of self-identification: they signal loyalty and affinity.

Origin
The term comes from the Hebrew word shibbólet (), which means the part of a plant containing grain, such as the head of a stalk of wheat or rye.Wahrig Deutsches Wörterbuch sixth edition, and   The context was the crossing of the River Jordan; according to E.A. Speiser, op. cit., 10, the medieval Hebrew commentators and most modern scholars have understood it in this alternative sense. 

The modern use comes from an account in the Hebrew Bible. How this word was pronounced was used to distinguish friend from foe. In the Book of Judges, chapter 12, the inhabitants of Gilead inflicted a military defeat on the invading tribe of Ephraim (around 1370–1070 BC). The surviving Ephraimites tried to cross the River Jordan to their home territory, but the Gileadites secured the river's fords to stop them.  

To identify and kill the Ephraimites, the Gileadites told each suspected survivor to say the word shibboleth (with voiceless postalveolar fricative). The Ephraimite dialect resulted in a pronunciation that, to Gileadites, sounded like sibboleth.  In the King James Bible: 

The concept of a shibboleth is still with us. It is any word, phrase, jargon or pronunciation which identifies a person as a member of a particular group.

 References 

Category:Words and phrases by language
Category:Hebrew language