Proband is a technical term used in genetics to describe the person or individual who is the focus of a genetic study or investigation. However, there are several synonyms that can be used to refer to the proband in everyday language. One such synonym is the term 'index case,' which is often used in epidemiology studies to describe the first person diagnosed with a particular disease. Another synonym for proband is 'subject,' which is commonly used in experimental studies to describe the individual under observation. 'Patient zero' is also a synonym used to describe the first person infected with a virus or pathogen in epidemiology or infectious disease studies.