A stock is a liquid that is flavorful, it's flavor is depended on simmering bones or vegetables. The 4 parts that fully make a stock are a main flavoring ingredient, water, mirepoix, and aromatics. This may also make the base for soups or sauces. You can easily add more flavor to it by adding mirepoix or aromatics.
1: White Stock: A clear and light-colored liquid made by simmering poultry, beef, or fish bones.
2: Brown Stock: A yellow-brown liquid made by simmering browned poultry, beef, calf or bones.
3. Fumet: It is like a fish stock and is made with fish bones. It is a stock with a lot of flavor.
4. Court Bouillon: This is a quick-cooking vegetable broth that has a lot of aroma and poaches fish or vegetables.
5. Glace: Also known as a "glaze". It has a jelly-like thickness and it is made from brown stock, chicken stock, or fish stock.
6. Remouillage: A stock made from bones that have been used in another stock before and it is known as a "weak stock".
7. Bouillon: The liquid that results from simmering meats or vegetables and it is commonly known as a "broth".
8. Jus: This is a rich, light stock which is used as a sauce for roasted meats. You add some stock in the pan and cook it and scrape any brown parts on the bottom of the pan if necessary.
9. Vegetable Stock: It is commonly made from mirepoix, shallots, and turnips. You can also add tomatoes, garlic, and seasonings to add flavor or darken the stock, but the tomatoes must be strained if used. A large amount of a particular vegetable is added, for example mushrooms for a mushroom stock.
I believe stocks are really important in cooking. They make the base to many dishes. They help you understand the different types and ways of cooking. They also help you get the precise flavor and texture you want. All stocks have a difference which means they may be combined with other dishes. If you know the different types of stocks, you will know how to make many more dishes from that.