Source : Webster's Revised Unabridged Dictionary (1913)

Enlist \En*list"\, v. t. [imp. & p. p. {Enlisted}; p. pr. & vb.
   n. {Enlisting}.]
   1. To enter on a list; to enroll; to register.

   2. To engage for military or naval service, the name being
      entered on a list or register; as, to enlist men.

   3. To secure the support and aid of; to employ in advancing
      interest; as, to enlist persons in the cause of truth, or
      in a charitable enterprise.

Enlist \En*list"\, v. i.
   1. To enroll and bind one's self for military or naval
      service; as, he enlisted in the regular army; the men
      enlisted for the war.

   2. To enter heartily into a cause, as if enrolled.

Source : WordNet®

enlist
     v 1: join the military
     2: as of aid, help, services, or support [syn: {engage}]
     3: engage somebody to enter the army [syn: {draft}, {muster in}]
        [ant: {discharge}]