"Red dwarf" is a term commonly used for a small and cool type of star. However, there are a few other synonyms that can be used to mean the same thing. One of these synonyms is a M-type dwarf, which refers to a type of low-mass star that exhibits a red hue. Another synonym is a flare star, which is a type of red dwarf that experiences sudden and intense bursts of energy. Finally, there is also the term ultra-cool dwarf, which can refer to a red dwarf or brown dwarf that has a very low surface temperature. Regardless of the synonym used, all these terms are used to describe the most common type of star in the universe.