What is that tiny saucepan with spout called and what is it used for?

Otherwise known as a butter warmer or milk pot, you will be surprised at how often you’ll turn to this tiny little pot. They usually hold anywhere from two to four cups of liquid, which is just right for warming up single-servings of hot chocolate or soup, melting butter, warming up syrup or making a roux. And the pouring spout is so handy! You can find these pots all over now, from the likes of Dansk, Brook Farm General Store, Williams Sonoma and even IKEA.