The word espresso is probably one of the most misunderstood things about the beverage itself, believe it or not. Beyond pronouncing it and drinking it, there's a rich etymology that might be able to shed a little light on the stuff.
Let's explore how this simple term fits into the latte lexicon, and what that might mean regarding your morning cup.
For one thing, and I'm sorry to have to say it: There's no "x" in espresso. (Unless of course you're a Spanish-speaker, in which case expresso actually is the correct word.) Confusingly, however, part of the origin of the term itself is based in the idea that the drink is prepared and consumed "expressly"—not only relating to speed, but also to its to-order nature, as in "made expressly for the person who requested it," rather than being siphoned out of a giant urn or a larger pot of brewed coffee.
Another misconception about the word espresso is that it explicitly demands something about the beans themselves, such as a particular origin or roast style. Sure, you can buy "espresso beans" at your local market, but genetically speaking they're no different than the beans you might use in a press pot or electric percolator.
The most common difference between "espresso beans" and any other type you'd find on those shelves is that coffees being made under pressure in an espresso extraction are often roasted in a different way—though not necessarily to a darker level. The pressure involved in making this type of coffee acts as something like a magnifying glass on a bean's particular predominant flavors (acidity in particular). Keeping that in mind, a roaster might decide to temper that brightness with a longer roast at a lower temperature, or any number of other techniques to bring out this or that characteristic in a coffee being developed specifically for an espresso extraction.
But no, espresso beans don't have to come from Italy (they don't grow coffee there), and they don't have to be roasted dark (some of the most interesting coffees are a bit lighter and brighter). They also don't even have to be blended: Single-origin espressos are popping up more and more in mainstream bars, as a way of offering customers a vastly different and specific flavor experience. The word espresso, therefore, doesn't describe the beans, but rather what the barista does with them to create the resulting beverage.
Just like you wouldn't go into a store and buy a bag labeled "French press coffee," you don't have to seek out specifically demarcated "espresso" beans: The word relates more to the brew method and the finished drink than to the raw ingredients.
That's a lot of language in one little cup!