Vexillology is the study of what?

Vexillology is the scientific study of the history, symbolism and usage of flags or, by extension, any interest in flags in general. The word is a synthesis of the Latin word vexillum ("flag") and the Greek suffix -logia ("study.") The constitution of the International Federation of Vexillological Associations (known by its French acronym, FIAV) formally defines vexillology as "the creation and development of a body of knowledge about flags of all types, their forms and functions, and of scientific theories and principles based on that knowledge."

A person who studies flags is a vexillologist; vexillography is the art of designing flags; one who does so is a vexillographer; an admirer of flags is a vexillophile.