Latte art, also sometimes described as cappuccino art, is a pattern or miniature sculpture produced within the froth that tops off milky coffee drinks such as cappuccino or latte.
Latte art is formed by mixing crema (the technical term for the liquid formed from coffee oil and water) and microfoam (the foam produced when air is passed through milk using a steam wand on an espresso machine). Since neither of these substances are stable (coffee dissipates and foam becomes liquid milk), latte art needs to be admired and appreciated as soon as it's completed, the careful designs simply 'dissolving' after a few minutes!
There are two varieties of latte art – one in which the foam is sculpted into a 3D pattern, and the other, more common approach, of 'etching' a pattern in the froth as the milk hits the surface of the coffee. Classic examples of latte art are patterns such as hearts, rosettes and ferns, but designs can be much more complicated, and include cartoon characters, intricate portraits, or even 3D animals. Some more serious 'latte artists' sometimes use colored syrups to 'paint' on the coffee and bring a vibrant twist to this unusual form of artwork. (Source: macmillandictionary.com)