Marination, also known as marinading, is the process of soaking foods in a seasoned, often acidic, liquid before cooking. The origins of the word allude to the use of brine (aqua marina) in the pickling process, which led to the technique of adding flavour by immersion in liquid. The liquid in question, the 'marinade', is often a vinegar (or other acidic liquid such as lemon juice or wine) and oil mixture. It can also contain herbs and spices.

It is commonly used to flavor foods and to tenderize tougher cuts of meat or harder vegetables such as beetroot, aubergine (eggplant), and courgette (zucchini). The process may last seconds or days. Different marinades are used in different cuisines. In Indian cuisine the marinade is prepared with yoghurt and other spices.

In meats, the acid causes the tissue to break down, allowing more moisture to be absorbed and giving a juicier end product. However, too much acid can be detrimental to the end product. A good marinade will have a delicate balance of spices, acid and oil.

Often confused with marinating, macerating is also a form of food preparation. Often soft vegetables, legumes or fruits are used and are also coated in a liquid. This process, again, makes the food tastier and easier to chew and digest.