In a nutshell: Smoked salmon is cured or brined, then smoked. Lox is cured, but not smoked.

Lox came about in the pre-refrigeration days as a way to preserve fish during transport. The authentic stuff is made from the fatty belly of salmon and salt-cured for about three months, according to Adam Caslow, the fourth-generation owner and co-CEO of Acme.

Smoked salmon uses up an entire side of salmon. The curing process varies depending on the size of the fish, says Lee-Allen. Smaller salmon are salt-cured, while the big ones weighing 20 pounds or more are halved and brined in a saltwater solution for anywhere from one to a few days.

Lox and smoked salmon—specifically Nova salmon, the type often casually referred to as "lox"—both have a silky, buttery texture. But true lox tastes much saltier, while Nova has an unmistakable smokiness.