I stumbled across an answer on Quora that describes the many different espresso-based coffee drinks.
In the author's answer, he defines a doppio as:
Double Espresso or twice the amount of coffee and twice the amount of water. Basically it describes two shots of espresso in one demitasse container.
He then goes on to define a short black:
A pure intense Italian favourite with a biting crème head. Contains 75ml of pure double shot (2) coffee essence made from 24gm of fresh ground coffee beans. Traditionally served in glass and is referred to as Espresso by European customers.
Is there any difference between the two if they're both double shots of espresso served in a glass container? Or is a short black a technical term referring to a specific ratio of coffee to water?