Why did Arthur Miller name his play "The Crucible," "The Crucible"?

I think that we have to go back to the definition of the
term, "crucible," in order to better understand its significance. The word "crucible"
refers to an object that withstands heat and does not melt easily.  It is able to
withstand pressure, external forces, and can endure a great deal.  This applies to many
of the characters in the play who either represent it or fail to do so.  Individuals
such as Elizabeth and John Proctor or Giles Corey would find themselves as bearing
similarity to a "crucible" as they endure an unimaginable lot in order to maintain their
own sense of dignity and, to quote John, their very "name."  Others, such as Reverend
Parris or Abigail, fail to uphold such ideals and are willing to melt under the social
pressure applied by others or under the heat of their own passions and self interest. 
In the end, the "crucible" ends up becoming how individuals respond to the pressures and
elements applied to them in times of crisis.