What's "the edge"?

Edge might mean leaf-level IoT devices. Plenty are smart enough to do their own trending or anomaly detection (ie ML), for example, and only report to the cloud the results of that.

So you have edge, cloud, and you might also ponder the "fog", where there's an intermediate aggregation layer. Think leaf devices in some building (edge) with some medium smarts done on prem (fog) before clouding it.

ML training on phones, IoT devices etc. They then share their learning with centralized ML running on normal servers.

Edge here means the client i.e. smartphones, browsers, or dedicated consumer side devices like the dashcam in the car