https://www.theverge.com/2018/7/26/17616140/google-edge-tpu-on-device-ai-machine-learning-devkit

Two years ago, Google unveiled its Tensor Processing Units or TPUs — specialized chips that live in the company’s data centers and make light work of AI tasks. Now, the company is moving its AI expertise down from the cloud, and has taken the wraps off its new Edge TPU; a tiny AI accelerator that will carry out machine learning jobs in IoT devices.

The Edge TPU is designed to do what’s known as “inference.” This is the part of machine learning where an algorithm actually carries out the task it was trained to do; like, for example, recognizing an object in a picture. Google’s server-based TPUs are optimized for the training part of this process, while these new Edge TPUs will do the inference.