What is "microfoam"

n. foam consisting of very small bubbles, specifically as an element in the steamed milk used to make certain types of latte coffee.

Microfoam is milk foamed using a steam wand on an espresso machine, used for making espresso-based coffee drinks, particularly those with latte art.

The opposite of microfoam is macrofoam (also called dry foam, in contrast to the wet foam of microfoam), which has visibly large bubbles, a style of milk commonly used for cappuccinos.