It's the same definition that the entire software industry uses and has for like a decade now. At this point crying that "serverless ackshually has servers!" is the same as pointing out that "free education isn't actually free!" as if the people using the term are unaware of this.
"Serverless" means that the developer doesn't need to think about the servers, and can interact with higher level abstractions on top of the physical servers to deploy their services.
"Serverless" means that the developer doesn't need to think about the servers, and can interact with higher level abstractions on top of the physical servers to deploy their services.