In the book Winkel in time what is the definition of sport?

Wallace talks because he had assumed he was a “moron.” Calvin tells Charles Wallace that he’s a “sport,” which means “a change in gene resulting in the appearance in the offspring of a character which is not present in the parents but which is potentially transmissible to its offspring."

When Calvin tells Charles that he's a sport in biology, he means that he is very good at that subject. What Charles says in response is: "A change in gene resulting in the appearance in the offspring of a character that is not present in the parent but which is potentially transmissible to their offspring."

This is not what a sport is.

Charles Wallace is simply flexing because he's a five-year-old who knows the Webster's Dictionary description of a mutation.