Lox is a salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than 5 millimetres (0.20 in) in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato or capers. Noted for its importance in Ashkenazic Jewish cuisine, the food and its name were introduced to the United States through Scandinavian immigrants, though it was popularized by Jewish immigrants. The term lox derives from Lachs in German and לאַקס (laks) in Yiddish, meaning "salmon".
Lox is traditionally made by brining the salmon in a solution of water, salt, sugars and spices (the brine).
Then the brined fish is cold smoked. This means it is placed in a smoker which stays at about 70 degrees °F. In this temperature range, foods take on a smoked flavor, but remain relatively moist. Cold smoking does not cook foods. This leaves the salmon with a beautiful red/pink color and a great texture. Of course, this process has many variations depending on cultures and types of salmon.