In Italian, the term "macchiato" translates as "marked" or "stained", meaning a stained or marked coffee. The macchiato is an espresso coffee drink, topped with a small amount of foamed or steamed milk to allow the taste of the espresso to still shine through. The origin of the name "macchiato" stems from baristas needing to show waiters the difference between an espresso shot and an espresso with a bit of milk in it. As the latter is "marked" or "stained" by the addition of milk, it was quickly given its name to highlight the addition.

Source: Nescafe