The phrase "most tertian" refers to something that occurs or happens most often or regularly. Some synonyms for "most tertian" include "commonly," "frequently," "regularly," "repeatedly," and "usually." These words are often used interchangeably, but can have slightly different connotations depending on the context in which they are used. For example, "regularly" suggests consistency and routine, while "frequently" implies a higher frequency of occurrence. Regardless of the synonym used, the idea of something happening most tertian suggests a pattern or habit that is worth paying attention to.