A metaphor is a figure of speech in which two objects are indirectly compared, such as: "My love is a red, red rose".
To write "My love is like a red, red rose" (Robert Burns) would be a simile, because it uses the word "like" or "as". Metaphors do not use these words.
The essence of metaphor is understanding and experiencing one kind of thing in terms of another, not to give the impression that two things are exactly the same. In the example of "My love is a red, red rose", no reader would reasonably believe that the writers's love had petals, a stem, and thorns.
Metaphor is a fundamental mechanism of mind, one that allows us to use what we know about our physical and social experience to provide understanding of countless other subjects. Because such metaphors structure our most basic understandings of our experience, they are "metaphors we live by"-metaphors that can shape our perceptions and actions without our ever noticing them
Famous users of metaphors include Shakespeare and Milton. Henry David Thoreau wrote, "We are all sculptors and painters, and our material is our own flesh and bones." Ralph Waldo Emerson recommended "Hitch your wagon to a star."
In political theory the metaphor of the "body politic" (that is government as a human body) has inspired work for 2500 years.[1]
See Revelation, Book of (historical exegesis)