A hot dog, or "frank", is a human food from Earth, primarily in the 20th Century, composed mainly of less desirable portions of meat processed into a cylinder and contained in a edible wrapper which is prepared by grilling over flame or boiling in water until completely heated.
Hot dogs were particularly associated as a snack food during games of baseball.
Kira Nerys was confused by the food's name, which outside of its direct meaning implies a heated canine, when Benjamin Sisko promised to treat her to the snack while the two watched a holodeck simulation of a baseball game. (DS9: "Starship Down")