aid-de-camp

from The Collaborative International Dictionary of English v.0.48

Aid-de-camp \Aid"-de-camp`\, n.; pl. {Aids-de-camp}. . [F. aide
   de camp (literally) camp assistant.] (Mil.)
   An officer selected by a general to carry orders, also to
   assist or represent him in correspondence and in directing
   movements.
   [1913 Webster]