Kubernetes is often shortened to k8s, which is often pronounced "kates," which is further shortened to k3s.
k3s is a pared down version of k8s, which is illustrated by the number 3 being chosen because it looks like an 8 sliced in half.
"What's with the name?
We wanted an installation of Kubernetes that was half the size in terms of memory footprint. Kubernetes is a 10-letter word stylized as K8s. So something half as big as Kubernetes would be a 5-letter word stylized as K3s. There is no long form of K3s and no official pronunciation."