Miller's choice of the term 'crucible' for his play concerning witchcraft, Puritanism, and morality often raises questions in the minds of the readers. First, a crucible is a piece of laboratory or metallurgical equipment used for refining metals. The metal would be placed into the container of the crucible and then was subjected to high temperatures which could be used either to burn away the metal's impurities or smelt some new compound of metal.
With this information in mind, Miller's title becomes a startling metaphor for the events that occur in Salem. The idea of the crucible suggests a trial by fire, in which the good and worthy are preserved and the false perish. The characters of the town must face and overcome their fears as well as prejudice, all within the incendiary events of the Salem witch trials.