The Collaborative International Dictionary of English v.0.48:

Enlistment \En*list"ment\, n.
   1. The act or enlisting, or the state of being enlisted;
      voluntary enrollment to serve as a soldier or a sailor.
      [1913 Webster]

   2. The writing by which an enlisted man is bound.
      [1913 Webster]

WordNet (r) 3.0 (2006):

enlistment
    n 1: a period of time spent in military service [syn:
         enlistment, hitch, term of enlistment, tour of
         duty, duty tour, tour]
    2: the act of enlisting (as in a military service)

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "enlistment":
   acceptance, admission, admittance, allurement, baptism,
   blandishment, booking, cajolement, cajolery, call, call-up,
   cataloging, chronicling, coaxing, compulsory military service,
   conning, conscription, continuous tenure, draft, draft call,
   drafting, engagement, enrollment, entering, entry, exhortation,
   hitch, hortation, immission, impanelment, impressment,
   inauguration, indexing, inducement, induction, initiation,
   inscribing, inscription, insertion, installation, instatement,
   intromission, inventorying, investiture, jawboning, levy, listing,
   lobbying, logging, matriculation, mobilization, muster, ordination,
   persuasion, posting, preaching, preachment, press, prison term,
   record keeping, recordation, recording, recruiting, recruitment,
   register, registration, registry, sales talk, salesmanship,
   selective service, selling, snow job, soft soap, solicitation,
   stretch, suasion, summons, sweet talk, tabulation, tenure, term,
   time, tour, wheedling, working on