I used to think the f-word meant to get a divorce because of the following twisted little logic trail: I'd once overheard a kid in a public bathroom asking her mum what that word meant; after much hesitation her mum answered that it was "something that married people do". Well, I already knew it was a bad word - and thus surely must mean a bad thing - and what could be worse for married people to do than to get a divorce?
A childhood belief about marriage

others believed things like this
- my husband believed, until recently, that the word "several" meant seven of something. — sheryl
- I used to believe that "nuptial" was a naughty word. I thought it meant nipple. XD— Sara Hagen
- i used to think the word "friendship" meant a special kind of rocketship that you went on with your friends.— chips ahoy!
- For years I heard the word "pedophile" and thought it meant a pedicurist's tool.— Lauren
- I fully believed, up until about 6 years old, that the word 'accident' was a noun that meant 'burnt toast'.— Karl Goetz
- In first grade, I thought that if I've never heard of a word before, then it wasn't a word.— Destiny