Those are PowerShell cmdlets - and follow PowerShell verb-noun naming convention. There is a finite set of "approved" verbs (though you can use your own) representing the "actions" you can perform against a resource (the noun part).

From within a PowerShell console I can "add" a lot of things. Try typing

    gcm -verb add

from a PowerShell console (gcm is alias for Get-Command and the command above will list all commands where "Add" is the verb).