The phrase "have dinner" is commonly used to refer to the act of eating a main meal in the evening. However, there are various other phrases that can be used as synonyms. Some examples include "dine," "eat supper," "indulge in a meal," "enjoy a dinner," "partake in an evening feast," "feast on an evening meal," "take dinner," and "sup." These phrases can provide diversity to your language when referring to the act of eating dinner, and can be used interchangeably depending on the context and preference of the speaker.