Metaphor has traditionally been construed as a linguistic phenomenon: as something produced and understood by speakers of natural language. So understood, metaphors are naturally viewed as linguistic expressions of a particular type, or as linguistic expressions used in a particular type of way. This linguistic conception of metaphor is adopted in this article. In doing so, the article does not intend to rule out the possibility of non-linguistic forms of metaphor. Many theorists think that non-linguistic objects or conceptual structures should also be treated as metaphors. Indeed, the idea that metaphors are in the first instance conceptual phenomena, and linguistic devices only derivatively, is the dominant view in what is now the dominant area of metaphor research: cognitive science. In construing metaphor as linguistic, the article merely intends to impose appropriate constraints on a discussion whose focus is the understanding and analysis of metaphor within contemporary philosophy of language.