Lox is a fillet of brined salmon. Lox is one type of salmon product served on a bagel with cream cheese, and is usually garnished with tomato, sliced onion, cucumbers, and sometimes capers. The other type of salmon product is smoked salmon.

The American English word lox is derived from the Yiddish word for salmon, לאַקס laks (cf. German Lachs, Swedish Lax), which ultimately derives from the Germanic word for salmon, *laks-. The word lox has cognates in numerous Germanic languages. For example, cured salmon in Scandinavian countries is known by different versions of the name Gravlax or gravad laks. (lax or laks means "salmon" in the Scandinavian languages.) Its wide distribution likely means it existed in its current form in a Proto-Indo-European language.

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.

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