The French term for a bundle of herbs used to flavor stocks is bouquet garni.
A bouquet garni usually combines thyme, bay leaf, and parsley, traditionally tied together with kitchen string. The bundle is simmered with soups, stocks, casseroles, and stews so it releases aroma without leaving loose herb leaves throughout the dish.
There is no single mandatory recipe. Cooks may add rosemary, basil, tarragon, savory, peppercorns, leek, celery, onion, or parsley root. The bundle is removed before serving, making it especially useful for clear stocks and refined sauces. It can also be enclosed in leek leaves, cheesecloth, muslin, or a tea strainer.
Bouquet garni is often confused with fines herbes, a finely chopped mixture of fresh herbs added directly to food, and mirepoix, a diced mixture of aromatic vegetables such as onion, carrot, and celery. A sachet d'épices performs a similar infusing job but is generally a small spice-and-herb bag rather than a tied bundle.