The Collaborative International Dictionary of English v.0.48:

Lockout \Lock"out`\, n.
   The closing of a factory or workshop by an employer, usually
   in order to bring the workmen to satisfactory terms by a
   suspension of wages.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lockout
    n 1: a management action resisting employee's demands; employees
         are barred from entering the workplace until they agree to
         terms

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "lockout":
   arrest, ban, bar, barring, bell, blockade, boycott, boycottage,
   check, checkmate, circumscription, cutoff, dead stop, deadlock,
   debarment, debarring, demarcation, embargo, end, endgame, ending,
   exception, exclusion, final whistle, full stop, grinding halt, gun,
   halt, inadmissibility, injunction, job action, narrowing,
   nonadmission, omission, outlaw strike, preclusion, prohibition,
   rejection, relegation, repudiation, restriction, revolt,
   rulebook slowdown, sick-in, sit-down, sit-down strike, slowdown,
   stalemate, stand, standoff, standstill, stay, stop, stoppage,
   strike, sympathy strike, taboo, tie-up, turnout, walkout,
   wildcat strike, work stoppage