In heraldry and heraldic vexillology, a blazon is a formal description of a coat of arms, flag or similar emblem, from which the reader can reconstruct the appropriate image. The verb "to blazon" means to create such a description. The visual depiction of a coat of arms or flag has traditionally had considerable latitude in design, but a verbal blazon specifies the essentially distinctive elements. A coat of arms or flag is therefore primarily defined not by a picture but rather by the wording of its blazon (though in modern usage flags are often additionally and more precisely defined using geometrical specifications). "Blazon" is also the specialized language in which a blazon is written, and, as a verb, the act of writing such a description. "Blazonry" is the art, craft or practice of creating a blazon. The language employed in "blazonry" has its own vocabulary, grammar and syntax, which becomes essential for comprehension when blazoning a complex coat of arms.