Question: Aren't they just the same thing? Are stock and broth interchangeable in recipes?
Answer: Stock and broth are very similar animals: water simmered with meat and/or bones, and usually some vegetables and aromatic herbs, then strained. (Though in the case of vegetable broth, meat is not used.) They're both utilized as a base for soups, sauces, and gravies. And, truth be told, some chefs use the words interchangeably. However, there are some generally accepted differences between stock and broth.
"Stock is predominantly [made with] bones and some trim," says Greg Fatigati, associate dean for curriculum and instruction for culinary arts at the Culinary Institute of America.
Broth, on the other hand, is usually made with pieces of actual meat, so it's richer.
"Broth tastes more like a finished product that can be served on its own," says Nils Norén, VP of culinary arts for the French Culinary Institute.
You can fortify stock with more meat to make broth.
For practical purposes, if you're making a recipe that calls for stock, you can use broth, and vice versa. If you're not making your own stock or broth, you can find canned or boxed broth at most grocery stores. (Stock is not widely available.) You can use this for any recipe that calls for stock, too, but try to buy the low-sodium version, because store-bought broth can be very salty.