I thought that 'clapping' was just ordinary, stationary clapping, and that 'a round of applause' was clapping whilst moving your hands in a circular movement.
BONUS: I thought that 'round of applause' was 'round of a claws'
A childhood belief about general

others believed things like this
- for the longest time every i used to think that Prince's "Raspberry Barret" said "round merry go round"— lin
- When I was little I saw the word "applause" and thought it said "applesauce"Anon
- i thought going to school was getting on the bus and driving round all day until they dropped you off. Anon
- I believed my dad when he said that he could see round corners. — Charisma
- I used to believe, the little round bandaids, were to cover bullett holes.Anon
- Up until I was nine my uncle told me that the round bales of hay were cow eggs.— Fred