I'm familiar with the serverless programming model e.g. GAE and AWS lambda etc. But what is "serverless mesh"? I googled it and found no definition.
I'm wondering if this was someone's mash up of "service mesh," and "serverless." As mentioned in the comments, both of these terms are used more than understood.
To clarify though, you run a service mesh in a cloud (serverless) context. I like the simple definition from an NGinX blog:
A service mesh is a configurable, low‑latency infrastructure layer designed to handle a high volume of network‑based interprocess communication among application infrastructure services using application programming interfaces (APIs).
To be specific, a service mesh can offer
service discovery, load balancing, encryption, observability, traceability, authentication and authorization, and support for the circuit breaker pattern.
Service mesh architecture is only one way to solve some of the problems serverless companies are trying to solve.