There are several synonyms for the term "lunch wagon," which is a mobile restaurant that serves food to workers or passersby. One common synonym is "food truck," which is a more modern term for a mobile restaurant that can be found at popular events or street corners. Another synonym is "roach coach," which has a negative connotation and refers to a food truck that serves low-quality food. "Mobile kitchen" is another synonym, which can refer to a food truck or a trailer that serves food. Finally, "canteen truck" is a synonym that specifically refers to a mobile restaurant that serves food to military personnel.