Olive loaf can mean two entirely different things, depending on the context. In the first sense, it is literally a loaf of bread which has been decorated with olives; the olives may be mixed into the dough, or sprinkled on top. In the second sense, it is a type of cured or baked meat which has been mixed with olives, classically pimento stuffed green olives, and it is designed to be eaten cold as a lunch meat. The meaning is usually clear from the context.
Olives are the cured fruits of olive trees. They can be cured in a wide variety of ways to create an assortment of textures and flavors. They have been a part of Mediterranean cuisine for thousands of years, and many people are quite fond of some olive varieties. The olives used to make olive loaves vary; black olives, for example, are common in breads, while larger green olives tend to be preferred in the meat version of olive loaf.
Olive loaf breads are quite common. They may be made with an assortment of flours, and they can include herbs, tomatoes, and other ingredients in addition to the olives. These breads pair well with a wide assortment of cheeses, and they can be served hot or cold. Olive rolls can be quite useful for picnics, while other types of olive loaf stray dangerously close to pizza, with toppings of cheese, olives, and fresh herbs. Many bakeries carry olive loaves, and they are also very easy to make at home.
In the sense of a lunch meat, an olive loaf is made with finely ground beef or pork which is mixed with whole stuffed olives and compressed either into a loaf pan or into a sausage casing. If the loaf is packed in a loaf pan, it is baked and typically has a short shelf life. Olive loaves which are turned into sausages can be smoked or brined to create a cured lunch meat like bologna which can last for several months under the right conditions.
Many delis carry olive loaf, both in whole and sliced form. It can be added to sandwiches or served as a cold cut with an assortment of other meats, cured vegetables, and cheeses. Once a cured olive loaf has been opened, it should be kept under refrigeration and used quickly, as it is no longer resistant to bacteria.