Heraldry is, formally, the art and science of using unique visual art to distinguish between individuals. This art is inheritable, distinguishing it from what the late Sir Anthony Wagner, Garter King of Arms, termed "proto-heraldry". It encompasses both coat-armor -- devices and connoyances, and arms -- as well as badges and mottoes, and has its roots in the troubadour culture of the early tournaments, as well as the military advisers who were versed in identifying the coat-armor of enemies on the field.
Genealogy, as a means to prove nobility and right to bear arms, is part of a herald's duty as well.
It also encompasses the more public speaking aspects: announcing competitors in tournaments, making proclamations, acting as voice to another, including ambassadorial roles.