Traditionally, "lox" referred to brined salmon, not smoked. "Nova brought in the smoked aspect, many years after lox was popular in the Lower East Side amongst Jews and East Europeans," says applehome. "Nova is from Nova Scotia—the Scotsmen who smoked anything and everything. But today, everything is everything—lox refers to cold-smoked salmon as well as non-smoked."
If you go to a traditional lox purveyor, though, be aware that the old meaning still applies: "Order lox, and they'll bring you lox!" says applehome. "It's pinkish and slimy, where the smoked stuff tends to be orange and more dry."
"Hard" or "hot" smoked salmon, with its flaky texture, is never called lox, though, thank goodness, says applehome.
Discuss: Nova Lox vs Regular Lox