There are a variety of words that can be used as synonyms for the term "luncheonette". One possible option is the term "diner", which refers to a small restaurant or cafe that typically serves breakfast, lunch, and dinner. Another potential synonym is "cafe", which typically refers to a smaller, more casual restaurant that serves light meals and snacks. Other possible options include "bistro", "eatery", "restaurant", or "coffee house". Ultimately, the best synonym for the term "luncheonette" will depend on the specific context in which it is being used and the associations and connotations that the speaker or writer wishes to convey.