There are several synonyms for the word "tummies" that you can use in different contexts. For example, the term "belly" is a commonly used synonym that can be used in casual conversations. Another appropriate synonym is "abdomen," which is a more medical term and can be used when referring to the area surrounding the stomach. Additionally, "gut" is another synonym for "tummies," which is a more informal term that is commonly used in the food industry. Finally, the term "stomach," while not technically a synonym for "tummies," is commonly used when referring to the digestive system and can be used interchangeably in some contexts.