Espresso machine?

I have found it strange what people define as an espresso machine. A machine that uses the espresso concept does not necessarily make an espresso in my book. But here is how is what I have found:

• mocha pot or stove pot, this is probably the original espresso device, but in todays term I would not consider in an espresso, the pressure is good, but the grinds are not very fine, and there is normally no crema
• Aeropress coffee maker - once again not an espresso, it produces the best coffee using course grinds
• Domestic espresso machines - I do not class these as espresso but rather espresso like. The grind is fine but not as fine as it could get, the machines do not have enough punch, perhaps I can be proved wrong
• Automatic espresso machines - Also an espresso like machine, with the Jura, probably the pick of the lot

So what is an espresso maker then. Well to me it has to have the following:

• The grind can be so fine that it clumps, i.e. it start to attach itself to other fine grinds
• The filter head MUST be metal, with out that it cannot produce enough backward pressure
• The tamp has to be manual, unless a tamp of 25kgs is guarnateed
• The machine must have accurate temperature control, so that the water is never hotter than 95 degrees.

So that is why I have found the definition espresso machine is too vague.