1. an old idea, saying or opinion that is often repeated and believed to be true, but that is not true or old-fashioned.
The saying, Sticks and stones will break my bones but names will never hurt me is a shibboleth. It is often repeated to children who have been victims of name-calling, and has been for at least a few generations, but is arguably untrue: ugly names CAN hurt, often as much as a physical blow.
2. a word or a way of speaking that identifies a person as belonging to a certain group. Example: Her accent was a shibboleth of upper class status.
The origin of the word is Hebrew, meaning “stream”. It was used in the Old Testament of the Bible, in Judges 12:6: 5 The Gileadites captured the fords of the Jordan leading to Ephraim, and whenever a survivor of Ephraim said, “Let me cross over,” the men of Gilead asked him, “Are you an Ephraimite?” If he replied, “No,” 6 they said, “All right, say ‘Shibboleth.’” If he said, “Sibboleth,” because he could not pronounce the word correctly, they seized him and killed him at the fords of the Jordan. Forty-two thousand Ephraimites were killed at that time.
This example from Judges corresponds with the 2nd definition of shibboleth, because the Ephraimites, apparently, did not have the “sh” sound in their language and therefore, when they could not pronounce it, it was a dead giveaway that they were from Ephraim or at least not from Gilead.