Learn English – Word for an idiom accepted as true but is actually false

idiomssingle-word-requests

According to "Wouldn't say boo to a goose", the idiom's meaning comes from the premise that geese are easily frightened. Assuming, as one commenter stated*, that this is factually false, is there a word or phrase describing this condition?

What is the word that means "In order to understand the meaning of an idiom, you must accept a false statement or premise as true"?

*I have to agree with the commenter. Nobody seems to have told the geese I've encountered of this fact.

Best Answer

Two often misunderstood terms come to mind.

You could say that the idiom begs the question:

To beg a question means to assume the conclusion of an argument—a type of circular reasoning. This is an informal fallacy, in which an arguer includes the conclusion to be proven within a premise of the argument, often in an indirect way such that its presence within the premise is hidden or at least not easily apparent.

People often use "begs the question" to mean "raises the question", but its original meaning was including an assumption in a statement about that assumption- such as the fact that geese are easily scared.

You might also call the idiom a factoid:

The term factoid can in common usage mean either a false or spurious statement presented as a fact, as well as (according to Merriam Webster and the Oxford English Dictionary) a true, if brief or trivial item of news or information. The term was coined originally in 1973 as a neologism by American writer Norman Mailer to mean a "piece of information that becomes accepted as a fact even though it’s not actually true, or an invented fact believed to be true because it appears in print." Since its creation in 1973 the term has evolved from its original meaning, in common usage, and has assumed other meanings, particularly being used to describe a brief or trivial item of news or information. So it is a factoid that "factoid" means something that is true.

People often use "factoid" to mean "a small fact", but its original meaning was a false statement that was repeated so often that people thought it was true- such as the fact that geese are easily scared.