I used to think that 'approximately' meant exactly, so, for example, I would describe something as 'approximately 3.2cm' with a clear emphasis on the first syllable to enhance the exactness. This went on into my early twenties I think...
when i was a child, i told my brother that "algebra" was a bad word so he would go around saying "algebra" all the time and sound like a moron...i was a deranged sister.
I used to think people were called "human beans".
i used to always wonder how one national guard could always guard the entire nation.
when my grandmother would want my mother to telephone her, she'd always say "Give me a ring". I thought she was literally telling my mother to buy her a ring. Since my mother would always agree, I imagined my grandmother to have some HUGE stash of rings omewhere...
I thought when you were in a cakewalk, you actually had to put your feet in cakes and walk around. I thought this was really gross and cried when my parents wanted me to participate in one at a church picnic.
When we were little my sister and I believed the word Poo to be a rude word but Pooh as in Winnie-the-Pooh was ok. So everytime we said the word Pooh we had to say "H" afterwards or we were being naughty. We used to have terrible arguments when we accused each other of not saying the H. And the song went: "Winnie the Pooh..H, Winnie the Pooh..H" Our parents must of thought we were mad!
Age 15. Playing a word game with my parents, I got the word 'Lingerie' on my card. Obviously it's only us romantics who like to linger, because they laughed their heads off at my naive pronounciation.
When we were younger and went on walks my sister always used to get the binoculars wrong. She used to ask my mum to pass her "big nockers" over so she could have a look out of them.
Believe it or not, I used to believe the word gullible was fake and went off telling everybody it wasn't in the dictionary. It took me years to find out that the saying "gullible isn't in the dictionary" was only a joke, and the people I told it to thought I was just saying that joke rather than really meaning it.
When I was a kid, I thought that a pair of panty hose was plural - and that if you were only talking about one leg, it was a panty ho.
When I was younger, my older sister convinced me that the words "sock" and "pervert" meant the same thing. You can imagine wha my mom said when I decared "there's a load of dirty pervets in my room".
I came home from school one day with a notice about Picture Day. I asked my mother if I could get a new pair of shoes. She asked me why I needed new shoes. I said that I wanted to look nice for Picture Day. She said nobody would be able to see my shoes in the picture. I pointed to the flyer and said "Look, it says right here, 'We will be photographing the entire student body.'" I don't think she stopped laughing for a solid two minutes.
I couldn't understand why no-one had invented a word for something that isn't big but at the same time isn't small so I used to express the concept with the word "little-big" or "big-little". It was a revelation to me when my mother asked me go to the shops for a medium sliced loaf (of bread) and I discovered that someone somewhere had actually solved the problem that was perplexing me at the time.
when i was about 4 i used to believe that 'on purpose' meant accidentally. whenever i spilled drinks i would shriek, "I did it on purpose, i did it on purpose!!!!"
The first time I ever heard of doing somersaults, I guess it was summer, and I thought somersaults were so called because someone was doing them in the summer. I supposed that if someone did the same thing in the winter, it would be a wintersault. As time went on and I never heard of wintersaults (or springsaults or autumnsaults either, for that matter), I assumed that there was some reason why somersaults were most likely to be done in the summer, hence the name. It seemed to make sense to the extent that summer is associated with outdoor activities, and I'd seen somersaults done primarily outdoors, probably because few people I knew would have had ample room to do them inside their houses.
I used to think that whenever I heard (or read..) someone say 'Nuff said. I thought that it meant that someone named Nuff said it. I used to think "Wow, this Nuff guy must be really popular and smart!"
I used to believe that "priceless" meant the same thing as "worthless". I was quite confused when a TV show mentioned that the fossils in a museum were priceless. Surely, those fossils must be worth SOMETHING...
I knew that 'playing hooky' was to skip school, so I logically drew the conclusion that one who plays hooky is called a hooker. Needless to say that when I exclaimed "Lets go be hookers!" to my friends, laughing ensued.
When i was about 5 years old i used to think 'Splendid' meant horrible, so one day when i left my hat at the park, and we went back to get it to find it gone, i exclaimed: "Maybe a Splendid robber took it!"