1530s, from M.Fr. metaphore, from L. metaphora, from Gk. metaphora "a transfer," especially of the sense of one word to a different word, lit. "a carrying over," from metapherein "transfer, carry over," from meta- "over, across" (see meta-) + pherein "to carry, bear" (see infer). Related: Metaphoric; metaphorical; metaphorically.
The comparison of one thing to another without the use of like or as: “A man is but a weak reed”; “The road was a ribbon of moonlight.” Metaphors are common in literature and expansive speech. (Comparesimile.)