what is the meaning of a cloud native app?
A cloud native app is basically an application "born in the cloud for the cloud."
"Born in the cloud" meaning it was created with the intent to be run in a cloud like environment instead of a traditional data center. You could in theory write a traditional app that runs in the cloud, but wasn’t designed for it. Nothing wrong with that, but just different intent.
"For the cloud" means that it takes advantages of cloud features such as autoscaling (ie stateless design) for highly availability. Meaning that if one component of the application fails, the whole does not fail. Microservices are part of this.