Definitions
Metonymy is a trope. It is a substitution of terms in which the substitution is suggested by some material or logical relationship—as opposed to metaphor where the tenor and vehicle are unrelated. The topos or logical relationship most often cited is that of cause and effect, but also consider antecedent-consequence. The tangent of a metonym can derive from anything that is contiguous, adjunct, proximate, or functional to the tenor.
Corbett and Connors: "substitution of some attributive or suggestive word for what is actually meant."[1]
Metonymy is another of Burke's (and Vico's) "four master tropes".[2 3] Northrop Frye also uses it to suggest an allegorical world view, as opposed to a mythic/metaphorical world view on the one hand or a descriptive/scientific world view on the other.[4] Following Vico, Stephen Pepper [5] and Hayden White[6] also consider metonymy along with the other "Master" tropes as a means of structuring knowledge and history.
Some Specific Types of "Metonymic Contiguities" (from "Semiotics for Beginners" by Daniel Chandler).[7] Each of these can also occur in reverse: cause for effect etc.
effect for cause "he's an accident waiting to happen"
object for user (or associated institution): "hired gun;" "social media"
substance for form "Gimme five"
place for event: "Woodstock" (for the epochal rock concert)
place for person: "please call home" (e.g. talk to your family)
place for institution (e.g. the White House for the executive branch)
producer for product: "she wears Abercrombie and Fitch"
controller for controlled: "I hit the median" (with my car).
object for object: "The pen is mightier than the sword,"
Examples from Literature
"As he swung toward them holding up the hand
Half in appeal, but half as if to keep
The life from spilling."
-Out, Out- by Robert Frost
The life from spilling is referring to blood and develops a link between the two.