Metonymy is a figure of speech in which something related to an object is used to represent the object itself.

For example, if a sailor is referred to an "an old salt," the figure metonymy is being used because "salt" refers to the salty sea upon which the sailor sails. If a sexist young man refers to a woman as a "skirt," he is using metonymy.

In his poem "Out, Out�? Robert Frost uses metonymy in the following lines when the main character of the poem has cut his hand off in a buzz-saw:

The boy's first outcry was a rueful laugh,
As he swung toward them holding up the hand
Half in appeal, but half as if to keep
The life from spilling out.

Can you identify the metonymy? What are the two terms (A and B) of this figure?