A pretzel was an Earth food which consisted of cooked, shaped dough that was usually covered in salt.
The 602 Club often had bowls of pretzels sitting on the bar. (ENT: "First Flight")
Doctor Phlox, Lieutenant Reed, and Ensign Mayweather once visited a bar that served pretzels. After Phlox puffed up his face to frighten a xenophobic Human there, he sat down and nonchalantly ate a pretzel. (ENT: "Home")
Doctor Bashir enjoyed a pretzel during a 2375 meeting in which the plot to take back Vic's lounge from Frankie Eyes and his cronies. (DS9: "Badda-Bing, Badda-Bang")