Shibboleth

Shibboleth has come to mean a party cry or watchword. It owes its origin as such to a passage in the Bible (Judges xii. 6) describing the war between Jephthah and the Ephraimites. When the latter tried to escape over the Jordan Jephthah's men intercepted them at the ford, and gave all passers the word Shibboleth to pronounce as a test. The Ephraimite would say Sibboleth and thus betray his nationality.