A highly concentrated drink brewed by forcing water - close to boiling point - through coffee beans. It's usually served as a single 'shot' (roughly 1 oz) of espresso or a double espresso made with two shots. Espresso is also the main base for a cappuccino, latte, and other coffee drinks.
A well pulled shot of espresso develops a thin, sweet foam on the top called crema.
eh-spress-oh