Lockout is a means used by industrial management to force workers to accept lower wages and worse conditions than they demand, that is, the lowering of the price of the only commodity which the workers have to offer, their labour. The factory is either closed down or operated by 'blackleg' labour and the workers are thus 'locked out'.
Growth in the strength of the trade union and labour movements has made it very difficult if not impossible to use the lockout, at least in the UK, but it is occasionally still used in continental Europe.