Examples of metonymy in poetry are substituting "slope" with "sheer" in "Annals of Sheer" by Les Murray, and substituting "gruff things" for "gruff" in Kevin Crossley-Holland's "The Grain of Things." In "Annals of Sheer" a sheep track "winds/ around buttress cliffs of sheer." Kevin Crossley-Holland says, "give me the gruff."
Metonymy is a figure of speech, which uses an abstract feature of an implied object rather than naming it directly. For instance, the U.S. and the Soviet Union might be referred to as "two great Cold War powers" rather than "countries." Metonymy is similar to, but different from, synecdoche. When using synecdoche, a poet refers to an object by naming only a part of it, as in "to have a roof over one's head" means having a whole house to live in, not just a roof.
A.E. Houseman uses metonymy in "Terrence, This is Stupid Stuff," in the lines "Look into the pewter pot/ to see the world as the world is not." Here "pot" stands for ale, and "world" refers to the experience of living life as a human. The poem "Out, Out" by Robert Frost contains metonymy that says "life" instead of "blood" in "as if to keep/ the life from spilling."