Vexillology is the study of flags. The word comes from both the Latin word "vexilla" "little sail" for flag plus the Greek suffix"-ology" that means "study of". The "vexillum" was a particular kind of flag used by the Roman legions. Vexillology is a kind of study of symbols related to heraldry. A person who studies flags is a "vexillologist", and a person who designs flags is a "vexillographer".