What is meant when someone says, "that was a defining moment?"*

Explanation:

When someone says that was a defining moment, they mean that it was an important, significant moment that changed something or someone. It is a exact moment where something happened to make something change.  

"get off of your lazy bum and come running with me or i'm dumping this pitcher of water on u " u say with a smile. she thinks your joking so she ignores you about 10 seconds later shes screaming wile water is dripping everywhere you say "here comes the second one! " then you here her say okay, your such a j e r k ! ill be ready in 5 put the pitcher down " she say in an angry tone. and you smile in victory

good enough?