A sandwich is a dish typically consisting of meat, cheese or vegetables used as a filling between slices of bread, or placed on a slice of bread, or more generally any dish in which bread serves as a container or wrapper for another food type. The sandwich began as a portable, convenient finger food in the Western world, though over time it has become prevalent worldwide.
There has been social media debate over the precise definition of sandwich, specifically whether a hot dog or open sandwich can be categorized as such. In the United States, the Department of Agriculture and the Food and Drug Administration are the responsible agencies for protecting the definition of sandwich. The USDA uses the definition, "at least 35% cooked meat and no more than 50% bread" for closed sandwiches, and "at least 50% cooked meat" for open sandwiches. However, the same USDA manual determines the burritos and fajitas are "sandwich-like", and frankfurters are "sandwich type", while stromboli is explicitly excluded. In Britain, the British Sandwich Association defines a sandwich as "any form of bread with a filling, generally assembled cold"; a definition which includes wraps and bagels, but potentially excludes dishes assembled and served hot, such as burgers.
Sandwiches are a popular type of lunch food, taken to work, school, or picnics to be eaten as part of a packed lunch. The bread is frequently coated with condiments such as mayonnaise or mustard to enhance its flavour and texture, but may be served plain ("dry"). As well as being homemade, sandwiches are also widely sold in various retail outlets and can be served hot or cold. Although savoury sandwiches, such as deli meat sandwiches, are in the majority, sweet sandwiches, such as a jam sandwich or a fluffernutter, form their own category.
The sandwich is named after its supposed inventor, John Montagu, 4th Earl of Sandwich. The Wall Street Journal has described it as Britain's "biggest contribution to gastronomy".