Microcanonical ensemble definition

I have one question regarding the definition of the micron-canonical ensemble (which also should apply to other types of ensembles). The definition from Wikipedia is :

"In statistical mechanics, the micro canonical ensemble is a statistical ensemble that represents the possible states of a mechanical system whose total energy is exactly specified."

When it says : "….possible states of a mechanical system", does it mean the possible microstates, whose weighted energy sum is the average energy of the system for a particular macrostate, in which the system is being found, or is it something else?