Metaphor is one of a variety of uses of language in which what is communicated is not what the words mean literally. It is, therefore, so to speak, a way of speaking of something by talking about something else. Thus, one has said (or written) X and thereby communicated Y. This characteristic of ‘indirectness’ is not alone sufficient to distinguish metaphors from other non-standard uses of language, but there is also a question as to whether metaphors in general are sufficiently similar to one another to permit a single, unified description of them. On one hand, metaphor has been a feature of poetry for centuries, conspicuous in the work of Homer and Shakespeare and countless other poets. But on the other hand, metaphor is pervasive in ordinary language, both in speech and in writing. It is not obvious that a single account of metaphor could be adequate to both poetic and more prosaic uses of figurative language.