Metaphor: A term or phrase that normally refers to one thing but is used in an unusual way, so that it now has a different referent and may have an unusual sense as well. Metaphors thus are used to suggest some kind of likeness or similarity between two things that might not immediately be seen as alike. There is much argument about the nature of metaphor, but increasingly philosophers agree that metaphors are essential to cognitive advances in science as well as religion and are not merely adornment that can be replaced by literal language.1
1. C.Stephen Evans, Pocket Dictionary of Apologetics & Philosophy of Religion (Downers Grove, IL: InterVarsity Press, 2002), p. 74.