Lox is a fillet of brined salmon.
Traditionally, lox is served on a bagel with cream cheese, and is usually garnished with tomato, sliced red onion, lettuce, and sometimes cucumber, which diners may or may not opt to add to the bagel. Less commonly, capers are added. 
Some American preparations of scrambled eggs or frittata include a mince of lox and onion.
The word lox is derived from the Yiddish word for salmon, לאַקס (laks), which ultimately derives from the Indo-European word for salmon, laks. The word lox has cognates in numerous European languages that also derive from one of the Indo-European languages.
Similar products 
- Nova or Nova Scotia salmon, sometimes called Nova lox, is cured with a milder brine and then cold-smoked. The name dates from a time when much of the salmon in New York City came from Nova Scotia. Today, however, the name refers to the milder brining, as compared to regular lox (or belly lox), and the fish may come from other waters or even be raised on farms.
- Scotch or Scottish-style salmon. A mixture of salt and sometimes sugars, spices, and other flavorings is applied directly to the meat of the fish; this is called "dry-brining" or "Scottish-style." The brine mixture is then rinsed off, and the fish is cold-smoked.
- Nordic-style smoked salmon. The fish is salt-cured and cold-smoked.
- Gravad lax or gravlax. This is a traditional Nordic means of preparing salmon. The salmon is coated with a spice mixture, which often includes dill, sugars, salt, and spices like juniper berry. It is then weighted down to force the moisture from the fish and impart the flavorings. It is often served with a sweet mustard-dill sauce.
Other similar brined and smoked fish products are also popular in delis and fish stores, particularly in the New York City boroughs, such as Sable (smoked cod), smoked sturgeon, smoked whitefish, and kippered herring.
See also