Mc·Don·alds /məkˈdɒnəldz $ -ˈdɑː-/ trademark the world's most famous fast food restaurant, which sells hamburgers, cooked chicken pieces, French fries, salads, and other types of fast food. Its best-known product is the Big Mac. There are thousands of McDonalds restaurants all over the world, and they are especially popular with children and young people. The company started in the US, and many people think of McDonalds as a typical part of the American way of life.