I think that we need to clear up some definitions here.

First, what is Kubernetes:

Kubernetes is a portable, extensible open-source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation.

Kubernetes has a number of features. It can be thought of as: a container platform - a microservices platform - a portable cloud platform and a lot more.

You can read more about what is and what is not Kubernetes here.

Second, what is a minikube? Minikube is an all-in-one install of Kubernetes, as it takes all the components of Kubernetes (Master Components, Node Components, potential Add-ons) and runs them in a single virtual machine. You can install Kubernetes in many different ways as listed in this documentation section, and if there is no minikube as you have asked, there still are many different ways to install minikube, for example, kubeadm as Murli said, kubespray, Google Kubernetes Engine, kops, Azure Kubernetes Service, etc.

I highly recommend you to try kelseyhightower/kubernetes-the-hard-way as it will walk you through setting up the cluster manually which will give you a good understanding on how things work inside Kubernetes - you can do that in Google Cloud Platform (there is 300$ free trial) or other platforms. There is also this guide in Kubernetes documentation where you can run Kubernetes on physical device step by step:

Note that it requires considerably more effort than using one of the pre-defined guides.

This guide is also useful for those wanting to understand at a high level some of the steps that existing cluster setup scripts are making.