The Collaborative International Dictionary of English v.0.48:

Adjutant \Ad"ju*tant\, n. [L. adjutans, p. pr. of adjutare to
   help. See Aid.]
   1. A helper; an assistant.
      [1913 Webster]

   2. (Mil.) A regimental staff officer, who assists the
      colonel, or commanding officer of a garrison or regiment,
      in the details of regimental and garrison duty.
      [1913 Webster]

   Adjutant general
      (a) (Mil.), the principal staff officer of an army,
          through whom the commanding general receives
          communications and issues military orders. In the U.
          S. army he is brigadier general.
      (b) (Among the Jesuits), one of a select number of
          fathers, who resided with the general of the order,
          each of whom had a province or country assigned to his
          care.
          [1913 Webster]

   3. (Zool.) A species of very large stork (Ciconia argala),
      a native of India; -- called also the gigantic crane,
      and by the native name argala. It is noted for its
      serpent-destroying habits.
      [1913 Webster]

WordNet (r) 3.0 (2006):

adjutant
    n 1: an officer who acts as military assistant to a more senior
         officer [syn: adjutant, aide, aide-de-camp]
    2: large Indian stork with a military gait [syn: adjutant
       bird, adjutant, adjutant stork, Leptoptilus dubius]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "adjutant":
   acolyte, agent, aid, aide, aide-de-camp, aider, assistant,
   attendant, auxiliary, best man, coadjutant, coadjutor, coadjutress,
   coadjutrix, deputy, executive officer, help, helper, helpmate,
   helpmeet, lieutenant, paranymph, paraprofessional, second, servant,
   sideman, supporting actor, supporting instrumentalist



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ADJUTANT. A military officer, attached to every battalion of a regiment.  It
is his duty to superintend, under his superiors, all matters relating to the
ordinary routine of discipline in the regiment.