Bacon is a meat product prepared from a pig and usually cured. It is first cured using large quantities of salt, either in a brine or in a dry packing; the result is fresh bacon (also known as green bacon). Fresh bacon may then be further dried for weeks or months in cold air, or it may be boiled or smoked. Fresh and dried bacon is typically cooked before eating, often by frying. Boiled bacon is ready to eat, as is some smoked bacon, but may be cooked further before eating.

Bacon is prepared from several different cuts of meat. It is usually made from side and back cuts of pork, except in the United States and Canada, where it is most commonly prepared from pork belly (typically referred to as "streaky", "fatty", or "American style" outside of the US and Canada). The side cut has more meat and less fat than the belly. Bacon may be prepared from either of two distinct back cuts: fatback, which is almost pure fat, and pork loin, which is very lean. Bacon-cured pork loin is known as back bacon.

Uncooked rashers of streaky pork belly bacon

Packaged smoked bacon

Raw bacon in a pan

The same bacon, cooked
Bacon may be eaten smoked, boiled, fried, baked, or grilled and eaten on its own, as a side dish (particularly in breakfasts in North America) or used as a minor ingredient to flavour dishes (e.g., the Club sandwich). Bacon is also used for barding and larding roasts, especially game, including venison and pheasant. The word is derived from the Old High German bacho, meaning "buttock", "ham" or "side of bacon", and cognate with the Old French bacon.

Bacon is distinguished from salt pork and ham by differences in the brine (or dry packing). Bacon brine has added curing ingredients, most notably sodium nitrite, and occasionally potassium nitrate (saltpeter); sodium ascorbate or erythorbate are added to accelerate curing and stabilise colour. Flavourings such as brown sugar or maple are used for some products. Sodium polyphosphates, such as sodium triphosphate, may be added to make the produce easier to slice and to reduce spattering when the bacon is pan-fried. Today, a brine for ham, but not bacon, includes a large amount of sugar. Historically, "ham" and "bacon" referred to different cuts of meat that were brined or packed identically, often together in the same barrel.