Q: Why does saying someone has bats in the belfry mean he (or she) is crazy? What do bats and belfries have to do with it? And, for that matter, why is a belfry called a “belfry”? Is it because of the bells?
A: Let’s begin with the word “belfry.” What comes to mind? Bats and bells, no doubt. That’s where bats hang out, that that’s where bells ring.
It’s reasonable to conclude that the origin of “belfry” had something to do with bells. But we shouldn’t jump to conclusions.
Linguists believe the word ultimately comes from the prehistoric Germanic word bergfrid, meaning a place of shelter.
But the word entered English in the 12th century via the Old French berfrei, a siege tower. No bells here.
For the first few hundred years, the word was spelled all sorts of ways in English (“berefrei,” “berfrey,” “barfray,” etc.), and it meant a siege tower, a movable structure used to protect attackers besieging a fortification.
The word wasn’t used for a bell tower until 1440, about the same time “bel” entered the picture (“belfray,” “belfroy,” “belfrie,” and finally “belfry”).
The lexicographers at the Oxford English Dictionary say the new “bel” spelling was undoubtedly popularized by the use of the term for a bell tower.
But let’s not leave the bats hanging.
For all we know, bats have taken up residence in belfries for hundreds of years. The expression “bats in the belfry,” though, comes from another meaning of “belfry.”
In the early 1900s, “belfry” was a slang expression for someone’s head. To have “bats in the belfry” was to be nuts—in other words, batty.
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