Heraldic describes things that belong to heraldry — the old system of coats of arms. A coat of arms is the painted shield, animals, and colours that a family, a city, or a club uses as its sign. A heraldic lion is a lion drawn in that special shield-painting style; a heraldic design is one made for those rules. The study itself is heraldry, not heraldic. Heraldic is the describing word: heraldic art, heraldic symbols. Dictionaries sometimes gloss it as “the study of coats of arms”, but that phrase names the subject; this word is the adjective for it. It comes from herald + -ic, probably following French héraldique. A herald was the officer who announced names and kept the rules of those shields. Though actually, in ordinary English herald now more often means a messenger or a sign of something coming, so students sometimes guess that heraldic means “announcing”. In careful use, heraldic still points at coats of arms, not at news. You will meet it in museums, history class, and descriptions of flags, school badges, and club crests. It is a formal, specialist word.