PowerShell, as a shell for working with objects, presents WMI classes in a very similar manner to .NET classes or any other object. There are a number of parallels between WMI classes and .NET classes.
A WMI class is used as the recipe to create an instance of a WMI object. The WMI class defines properties and methods. The WMI class Win32_Process is used to gather information about running processes in a similar manner to the Get-Process command.
The Win32_Process class has properties such as ProcessId, Name, and CommandLine. It has a terminate method that can be used to kill a process, as well as a create static method that can be used to spawn a new process.
WMI classes reside within a WMI namespace. The default namespace is rootcimv2; classes such as Win32_OperatingSystem and Win32_LogicalDisk reside in this namespace.