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 visual depiction of a coat of arms or flag traditionally has considerable latitude in design, while a blazon specifies the essentially distinctive elements; thus it can be said that a coat of arms or flag is primarily defined not by a picture but rather by the wording of its blazon (though often flags are in modern usage additionally and more precisely defined using geometrical specifications). Blazon also refers to the specialized language in which a blazon is written, and, as a verb, to the act of writing such a description. This language has its own vocabulary, grammar and syntax, or rules governing word order, which becomes essential for comprehension when blazoning a complex coat of arms.