Espresso
Espresso is a strong black coffee made by forcing steam through dark-roast aromatic coffee beans at high pressure in an espresso machine. A perfectly brewed espresso will have a thick, golden-brown crema (foam) on the surface. If the crema is good, the sugar you add will float on the surface for a couple of seconds before slowly sinking to the bottom.
Espresso is the foundation for a wide variety of specialty coffee drinks, such as the cappuccino, but many aficionados and purists insist that adding anything (besides a bit of sugar) is blasphemy, akin to Scotch lovers mixing their single malt with Coke.