: a figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them (as in drowning in money); broadly : figurative language
"Is 'Moby Dick' a metaphor for the struggle of trying to read 'Moby Dick'?" – Tweet from @ColbertReport, August 16, 2013
About the Word:
The Greek ancestor of metaphor meant "to transfer; change." The metaphor transfers a name for something to another thing in order to suggest likeness between the two, as in Homer's repeated use of "the wine-dark sea."
A mixed metaphor combines different metaphorical images or ideas in a way that is foolish or illogical, like this quotation reported in the Chicago Tribune in 2007: "So now what we are dealing with is the rubber meeting the road, and instead of biting the bullet on these issues, we just want to punt."