Funny story -- Google Container Engine was the obvious name for that product but the TLA for it (GCE) conflicted with Google Compute Engine. We broke the tie by deciding the TLA for Container Engine would be GKE. The 'K' is a nod toward the Kubernetes underpinnings.
Google Compute Engine itself was difficult to name. There were those that were pushing for Google Compute Cluster. But I veto'd as the TLA would have been GCC or GC2. Both would have been awful.
Naming is hard.