"messenger, envoy," late 13c. (in Anglo-Latin); c. 1200 as a surname, from Anglo-French heraud, Old French heraut, hiraut (12c.), from Frankish *hariwald "commander of an army" or a similar Germanic source, from Proto-Germanic *harja "army" (from PIE root *koro- "war;" see harry) + *waldaz "to command, rule" (see wield). The form fits, but the sense evolution is difficult to explain, unless it is in reference to the chief officer of a tournament, who introduced knights and made decisions on rules (which was one of the early senses, often as heraud of armes, though not the earliest in English).