It kinda depends where you’re getting your coffee. Historically, the cappuccino gets its name from its color, which is supposed to match that of a capuchin monk’s robes, as an indication you have the ratio of coffee and milk right. These days, it basically means equal parts espresso, steamed milk, and foam. A latte is mainly steamed milk, with one or two shots of espresso, and a thinner layer of microfoam on top. A flat white… is supposed to be kind of a midpoint a cappuccino and a latte, but there’s really no hard and fast rules, and the ratios of all three will vary from one coffee shop to another. At chains like Starbucks the difference between a flat white and a cappuccino can be pretty subtle, and all three drinks are probably drowned in sugar syrup anyway.