A snack is a portion of food, smaller than a regular meal, generally eaten between meals. Snacks come in a variety of forms including packaged snack foods and other processed foods, as well as items made from fresh ingredients at home.

Traditionally, snacks are prepared from ingredients commonly available in the home. Often cold cuts, fruit, leftovers, nuts, sandwiches, and the like are used as snacks. The Dagwood sandwich was originally the humorous result of a cartoon character's desire for large snacks. With the spread of convenience stores, packaged snack foods became a significant business. Snack foods are typically designed to be portable, quick, and satisfying. Processed snack foods, as one form of convenience food, are designed to be less perishable, more durable, and more portable than prepared foods. They often contain substantial amounts of sweeteners, preservatives, and appealing ingredients such as chocolate, peanuts, and specially-designed flavors (such as flavored potato chips).