This is not to be confused with an adjutant, who is the senior administrator of a military unit.
The first aide-de-camp is typically the foremost personal aide.
The badge of office for an aide-de-camp is usually the aiguillette, a braided cord in gold or other colours, worn on the shoulder of a uniform. Whether it is worn on the left or the right shoulder is dictated by protocol.
In Argentina, three officers (one from each armed service, of the rank of lieutenant colonel or its equivalent), are appointed as aide-de-camp to the president of the republic and three others to the minister of defense, these six being the only ones to be called "edecán", which is one Spanish translation for aide-de-camp ("ayudante de campo" is another – "edecán" is a phonetic imitation of the French term; "ayudante de campo" is a word-for-word translation of it).