1777, quick for aide-de-camp (1660s), which can be French and implies "camp assistant" (see help (n.)).
a person who will act as assistant
- an officer who acts as military assistant to an even more senior officer
- online assistance
See Renouard's Annales de l'imprimerie des Aides (Paris, 1834); Didot's Aide Manuce (Paris, 1873); Omont's Catalogue of Aldine publications (Paris, 1892).